Unbeknownst to What If...? fans at the time of release, episode 7 exploring a universe where Thor is an only child was to be the calm before the storm of the final two episodes of the first season, with plenty of comic relief. The threat of this episode comes from Thor himself due to him wanting to make the most of his mother being away and throwing a huge party.
Due to the fun nature of the episode, it is only natural that it ends up being one of the funniest What If...? episodes of the first season, with many fun twists, appearances from beloved characters, and several memorable moments and quotes.
10 "Release The Foam" - The Grandmaster
Although the concept and image of Grandmaster being the DJ at a party is funny enough, the delivery of his line, "Release the foam," while DJing one of the parties makes it even more hilarious. Jeff Goldblum once again voicing this character only adds more to this.
With the close up of his face while the beat drops and the foam is released, it would be easy to forget that this is a Marvel show. However, if a party of this scale was going to take place in real life, things like this would happen, making it only natural that unassuming characters from the MCU would fall into these roles.
9 "Wait, Are You Guys Calling A Podiatrist?" - Darcy
When the agents of shield, Rumlow, Coulson and acting director Hill are concerned that the party atmosphere is spreading, they are forced to resort to calling Captain Marvel on the '90s pager that was given to Fury to use in emergencies.
Darcy being Darcy, she comments on how it looks like something her dad used to own and asks the question "Wait, are you guys calling a podiatrist?" Nobody knows if she is being serious or not so they go ahead and use it regardless, brushing aside Darcy's question or joke. Darcy's role in the MCU is largely for comic relief, and while many of her lines and quotes slip under the radar, this one landed the humor well.
8 "I Now Pronounce You Darcy And The Duck, Uh-Huh" - Elvis
During all of the party shenanigans, Darcy gets married to Howard the Duck with an Elvis impersonator officiating the wedding, in typical Vegas fashion. "I now pronounce you Darcy and the Duck, uh-huh," in an Elvis accent is not something you would expect to hear ever, let alone in a Marvel series.
Having a moment like this that signifies Vegas shenanigans as part of Thor's huge party on Earth fits perfectly and legitimizes it somewhat while adhering to Earth "traditions."
7 "Ball Cannons" - Korg
The circumstances surrounding Maria Hill becoming the acting director are amusing once it is revealed how Nick Fury was knocked unconscious. He was knocked to one side by a rampaging Korg who just wanted to jump into the pool and keep the party going, shouting "Ball Cannons" as he unwittingly launched Nick Fury to one side.
Had it been any other character to do so, with different or no dialogue, it wouldn't have had the same effect, and Fury would get more of the viewers' sympathy. However, as it isn't a detail significant to the overall party plot, having the humorous scene that added fuel to S.H.I.E.L.D hating Thor's party escapades even more made perfect sense.
6 "Did You Know That Midgard Is The Birthplace Of The Snuggie?" - Thor
The whole concept of Thor being an only child is the overarching theme of this episode, and it is a fun exploration of a version of Thor that is still a somewhat-spoiled teenager at heart. His scramble to hide evidence of all his party antics from his mother highlights the classic nature of a teenager hosting a party while their parents are away.
Any interaction that reduces the mighty God of Thunder to a bumbling mess makes for hilarious television, and him trying to make awkward small talk with his mother, especially with "Did you know that Midgard is the birthplace of the snuggie?" only furthers this.
5 "Prepare Yourselves, For The Partaaaaay Prince" - Thor
When Thor arrives on Midgard, the first thing he says in an initially ominous tone is "Prepare yourselves... for the party prince". People appear to be scared of the impending warning before he finishes his sentence and it is made abundantly clear that he is there to show everyone a good time.
The way in which Thor emerges from the darkness and reveals himself as he says "party prince" and gestures, instantly reassures everybody and the party can commence. This sets the precedent for the entire episode, with Thor instigating a party on a scale that no one has previously seen before.
4 "My Name Is Thor, With A T And An R And An O And A H, But Not In That Order" - Thor
When Captain Marvel arrives on the scene to confront Thor and shut the party down, Thor's initial response is to introduce himself, but he spells his own name incorrectly. This is once again playing into this visage of the spoiled only child who perhaps isn't entirely all-there.
Thor and Darcy are the main points of comic relief throughout the episode but it is lines like "My name is Thor, with a T and an R and an O and a H, but not in that order", that steal the show in terms of their hilarity. It just reaffirms the situation to Captain Marvel that Thor is just a hothead who likes to party, not an especially malicious threat to humanity.
3 "I Don't Know Anything About Horse Gods, But I Do Know How To Bring The Thunder" - Thor
When speaking to Thor for the first time in this universe, Jane asks Thor if he really is Thor the Norse God of thunder, but with Thor being his witty yet somewhat witless self, he replies about not knowing anything to do with horse gods.
Whether he genuinely doesn't understand the term Norse, he misheard or he was just being funny, this line was still hilarious, as is a consistent theme with this version of Thor in the What If...? series.
2 "You Know There's A Midgardian Word For Women Like You. Party Pooper" - Thor
When Captain Marvel intercepts Thor as his parties are getting out of control, Thor gets frustrated and annoyed at the thought of the party ending. The delivery of his line "You know there's a Midgardian word for women like you. Party Pooper," with dramatic music and a pause between the sentences, gives the implication that a rude or offensive name might have been said instead.
"Party Pooper" however, is exactly what Thor, his friends and all of their extravagant parties consider as an enemy, as it's essentially what would destroy their fun.
1 "You're My Brother From Another Mother, Man. I Mean That" - Loki
With the whole premise of this particular episode of What If...? centering around Thor being an only child, the fact that they would reference Thor and Loki being "brothers" in the sense of really good friends, is a hilarious touch.
In this universe, Loki is revealed to be an Ice Giant, which makes for some incredibly humorous interactions. "You're my brother from another mother, man" is heartwarming, hilarious and also interesting at the same time. The idea of the multiverse and different timelines in general is that most universes have had drastic changes making them unique, but most still possess some of the same themes albeit with different representations, such as this universe's interpretation of Thor and Loki's brotherly bond.