In comparison to the bleak, overly gritty tone of the CW's Arrow, the spinoff series, The Flash was a breath of fresh air. Where Arrow was dark, Flash was full of lighthearted, classic superhero fun. But, the show couldn't coast on this light-hearted success forever and, like ArrowThe Flash very quickly declined in quality. Sure, there are points where the show is still enjoyable, and season four seems to be returning to the fun nature and tone that made the first season so great, but there are still plenty of times when The Flash was trash.

RELATED: 20 Times Gotham Went Too Far

The thing with the Arrowverse shows, and CW shows in general, is that they tend to burn through story and twist ideas pretty fast. It's almost as if the show is constantly on the edge of losing a huge amount of viewers, so stakes have to be frequently raised further and further. The only problem with this is that shows like The Flash and Arrow already have pretty high stakes to begin with, resulting in these shows burning through twists, new ideas and gimmicks pretty quickly. The Flash is perhaps the biggest victim of this writing approach, and these 15 times it caused the show to be less than what it could have been.

15 FIRESTORM

Remember that hugely divisive scene where the S.T.A.R. Labs team look at the footage of the particle accelerator explosion and find the energy ghost (or whatever it was) of Ronnie Raymond combining with Martin Stein? Yeah that might have been one of the weakest looking scenes in superhero television history -- it was just basically just Robbie Amell's somber face on a cloud of particle energy.

This may have been a contentious way to introduce Firestorm into the Arrowverse, but there was plenty to take issue with before it. The combined scientists were found living under a bridge, eating trash and stalking Caitlin and Mrs. Stein. Every appearance of the hobo Ronnie was just plain cringeworthy, as was his transition into a superhero and Ronnie's eventual death. It was a strange choice to include Firestorm in The Flash in the first place, and his introduction was handled terribly.

14 ALTERNATE EARTHS

Like the series' main character, The Flash moved a bit too fast. Meaning, high-concept-sci-fi elements like the speed force, speedster time travel and alternate earths were introduced way too fast into the lore of the show. These elements, especially the alternate Earths, got out of hand VERY fast.

Earth-2 was introduced in season two with the arrival of Jay Garrick and the various meta-humans he sent from his dimension to take out The Flash. After the first half of season 2, all the alternate Earths really did for the series were provide an excuse to bring back "dead" characters, give easter eggs and fan service to comic book readers and add way too many variables. Simply put, alternate earths just make a mess of things.

13 HARRISON WELLS

Speaking of alternate Earths, some of the most contentious things to come out of their introduction into the show were the two returns of Harrison Wells. Harrison was a great part of season one, dying at the end. However, this wouldn't be the last time we would see Tom Cavanagh on The Flash. In season two, he came back as the Harrison Wells of Earth-2, later leaving to return home, being replaced by "H.R. Wells," the Harrison Wells of Earth-19.

Though Cavanagh deserves a good amount of praise for his range in playing three different versions of the character (four counting pre-S.T.A.R. Labs Wells), it's not exactly clear why Wells keeps coming back. Even worse is that H.R. seems to have only been included for comedic relief, which wouldn't have been necessary if season three wasn't so dark.

12 ZOOM REVEAL

Season one's big reveal worked incredibly well. We knew that Wells was Reverse Flash, but the tension and excitement remained for the entirety of the story arc. In season two, Zoom was the big bad, and he was revealed to be Jay Garrick, or rather an evil speedster pretending to be Jay Garrick. Season two wasn't terrible, but this big bad reveal was probably the part that upset some fans the most. For many, it came out of nowhere, and felt more like a twist written for ratings than an organic story development.

It also raises a lot of questions, especially about the complexity of Zoom's plan to steal Barry's speed. It's a huge continuity mess that wasn't handled well. Even worse, the "mysterious masked big bad" approach to Arrowverse shows only became more stale, predictable and overdone after Zoom, the trend being incorporated by both The Flash and Arrow to, some might say, boring results.

11 WALLY'S INTRODUCTION

Kid Flash DC CW TV

In the comics, Wally West was Iris West's nephew, given super speed by recreating the accident that gave The Flash his powers. In CW's The Flash, Wally is Iris' long lost brother, not much younger than her or Barry. This Wally was introduced in what many fans felt to be a sloppy way, and his induction into team Flash is even worse.

After finding out that he had a long-lost son, Joe West does everything to try to connect with him, and Wally turns him away at every chance, until he just doesn't. The West family reuniting is just a bit too "happy ending," and the way that Wally joins Team Flash and eventually becomes Kid Flash — a name not all the fitting to a twenty-something character — is rushed and glossed over at best.

10 THE RIVAL

Oh man, that costume is terrible, isn't it? It's like if Hawkman suddenly decided he wanted to have a lightning and lava motif, but still kept the winged headpiece. That's not even mentioning that the nose on the cowl is just plain ugly. Seriously, what's going on there? Is it melting? Okay okay, enough about how he looks, let's talk about The Rival's role in season three, which many fans took issue with.

He was introduced as the main villain in the Flashpoint timeline, arch nemesis to Wally West, who was the only speedster of this alternate world. His motivation for terrorizing the city is pretty weak -- he wants the people to know he has no Rival... and that's it. Most fans of the Flash wanted more out of a new nefarious speedster, and were not happy with his arguably generic villainous posturing.

9 ALCHEMY

After the reveal of Zoom's identity, both The Flash and Arrow started to rely a bit too heavily on the "masked big bad" storyline for each season. In season 3 of The Flash, there were two of these villains/storylines, Savitar of course, and his underling, Alchemy. Alchemy and Julian Albert were introduced close together, so the twist that he was Alchemy was predictable to many fans, at best, and boring at worst.

Alchemy had the ability to restore the powers and memories of the Flashpoint timeline, a strangely specific power that some fans thought was unnecessary. For one thing, it's a strange ability to have since it only has one specific use. Further, why do we need "new" meta-humans to be introduced in the first place? Sure, Savitar might need minions, but why not just recruit the ranks of meta-humans who are still running around after the particle accelerator explosion? Or are they all dead now?

8 FLASHPOINT

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Speaking of Flashpoint, many members of The Flash's preexisting, built-in comic book audience thought it was a low point for the series. Though it shared the same initial plot of the groundbreaking comic book series -- Barry going back in time to stop his mother's death -- the aftermath is far different, and disappointed fans of the comics, or the animated film of the same name.

This alternate timeline only lasts a single episode and the negative side effects of putting things back to "normal" are pretty much resolved in a few episodes. It also provides a convoluted way to introduce new villains, when more main-timeline meta-humans could have been used instead. In retrospect, much of the fanbase thought it was an ill-advised move to use the Flaspoint storyline in the show, especially when it was changed so much.

7 SAVITAR REVEAL

The Flash vs Savitar

Fans of the show found Savitar largely convoluted and confusing; his motivations, origins and reveal making little to no sense. Why would he want to create the dark timeline that created him? Why would he become bad in the first place? If the other Barry trapped him in the Speed Force, couldn't he just get himself out?

Basically, Barry made a bunch of time clones to fight Savitar, who killed all but one, including the original Barry. Afterwards, Barry's friends reject the remnant as a time clone, not the real Barry. Shunned, this remnant decides to get revenge by becoming Savitar. When fans learned this origin of Savitar, the internet predictably went to war, with many feeling that such a turn of events was completely out of character for both the Team and Barry himself. His was a weak motivation at best, and a profoundly tone deaf one at worst.

6 FUTURE BARRY

Another aspect of season three that riled was aftermath of Iris' "future death," witnessed by Barry after accidentally traveling to the future. We'll get to how this affected season three soon, but first let's talk about the future this created. In the episode, "The Once and Future Flash," Barry travels to the future in hopes of finding out Savitar's identity so he can prevent Iris' death.

When he arrives, he finds a dark timeline where all of his friends are different after the loss of Iris. Caitlin is in jail as Killer Frost with Julian assigned to keep her alive. Cisco has robotic hands after fighting Killer Frost. Joe constantly mourns his daughter's death and Wally suffered a spinal injury from Savitar. It's all very grim and dramatic, and many fans found the Barry in this future too much of an emo cliche with few redeeming qualities.

5 UNANSWERED QUESTIONS

Almost all scenes in recent seasons of The Flash either take place in S.T.A.R. Labs or at the scene of a crime, and even the superhero fight scenes seem to occur less these days. This raises a few questions that are, frustratingly, still unanswered.

The first question most fans want answered is what exactly is going on with S.T.A.R. Labs? Before the museum was opened, which raises a ton of questions on its own, how did they keep the lights on? Heck, how did the "employees" who make up Team Flash even feed themselves? Barry, Joe and Iris all have day-jobs, which are rarely seen these days, but how was the lab being funded after the particle accelerator fiasco? Furthermore, how do they get away with housing an illegal prison and using Barry and Joe's police jobs to cover up their vigilante operation?

4 WHO CARES ABOUT KILLER FROST?

The Flash draws quite a bit from The New 52 line of DC comics, including the reboot's interpretation of villain Killer Frost. Unlike previous versions, this Killer Frost was named Caitlin Snow and, being a sort of heat vampire, had an attraction to Firestorm, someone she sought out for his infinite warmth. This "relationship" was adapted into the relationship between Ronnie Raymond and Caitlin Snow on The Flash.

These versions of the characters were engaged before the particle accelerator exploded, which would eventually lead to Caitlin developing ice-based powers and a secondary evil persona. Caitlin's struggle with her Killer Frost persona was derided by many fans. She often swings back and forth between being Killer Frost and Caitlin, and some fans thought the reasons for her switch weren't written convincingly enough.

3 BAD ROMANCE

As with most CW shows, romance is a big part of the plot, and The Flash is no different. The series has a lot of romantic subplots, especially in season three. Some of these start out interestingly enough, but fans have argued that many of the show's pairings don't really contribute much to the series as a whole. Take, for example, Cisco and Gypsy, their interactions have, for some, become cliche, with him smooth talking and her suddenly liking him.

Most of the relationships on the show follow this formula, two characters who don't really have reason to like each other suddenly being paired together. It can be seen with Julian and Caitlin and a long list of other couples on the show. The romance on The Flash makes sense in small doses, like with Barry and Iris (though some fans have turned against that pairing, too), but it's become a far too large part of the show for a portion of the viewing audience.

2 THE MUSICAL CROSSOVER

Grant Gustin Melissa Benoist Duet

Both Grant Gustin and Supergirl actress Melissa Benoist are alumni of the Fox series Glee, so both actors can sing. Thus, from a marketing/ratings point of view, some kind of musical crossover between the two makes sense. Regardless of the reasoning, fans were excited when the musical crossover was announced, especially when another Glee alumni, Darren Criss, was cast as Music Meister. However, in the end, "Duet" wasn't as universally beloved as expected.

There are only two original songs written for the special, with three covers taking up most of Barry and Kara's singing. Furthermore, one of the original songs is performed by Barry outside of the musical fantasy world while proposing to Iris and it's largely regarded as being "cringeworthy." The story for "Duet" is somewhat interesting, but aside from the vocal performances, which are the one redeeming trait of the special, the episode as a whole fell rather flat.

1 PREVENTING IRIS' DEATH

iris-west-death-header

Season three of The Flash had the darkest tone of any other season. It revolved mostly around preventing Iris' death. After traveling to the future and witnessing Savitar kill Iris, Barry and team Flash try to change different moments and headlines in an attempt to alter the future and save Iris.

For a series that thrived on lighthearted superhero fun, this is such a dark turn, with even darker motivations. Instead of fighting crime with his powers for the sake of doing the right thing, every one of Barry's actions in season three is to prevent the murder of Iris. A noble motivation, yes, but still a dark one that brings the mood down for most of the season. Barry even leaves both Iris and Joe out of the loop at first, which some fans thought was a strange and unnecessary choice that only serves to provide melodrama for a few episodes.

Which parts of The Flash did you think could have gone better? Let us know in the comments!