WARNING: The following article contains spoilers for the latest episode of The Big Bang Theory, "The Decision Reverberation," which aired Thursday on CBS.

For the better part of 12 years, The Big Bang Theory's Leonard Hofstadter has been at the mercy of Sheldon Cooper's whims. Since the hit sitcom's premiere, Leonard has bent over backward to tend to the many peculiarities of his roommate and best friend, even going as far as to sacrifice his own happiness -- and health.

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But in this week's episode, "The Decision Reverberation," Penny has had enough: After witnessing Leonard again submit to everyone's will, she urges him to stand up for himself. It takes a bit to convince Leonard, who's a people-pleaser, but eventually he tries on that particular hat, and it leads to something he never expected.

Leonard starts by deciding what he and Penny will do on their date night, without taking her feelings into consideration for the first time, but it isn't long before he goes further: He changes Sheldon's meticulous food schedule, takes a different route to work, and even steals Sheldon's signature spot. Then, after seeing the benefits of standing up for himself, Leonard decides to make a proposal for a new project to his boss, Caltech President Siebert, and he won't take no for an answer.

Filled with newfound confidence, Leonard decides to go after his dream job as lead investigator on a plasma team. Unfortunately, the university's president isn't convinced, and he shoots down the proposal. But before Leonard has the chance to quit and move on to another university, Siebert insists he doesn't want to lose him. For that reason, he offers him another position: co-lead on a photon entanglement team. That's mumbo jumbo for those of us who don't understand physics, but Leonard is ecstatic about the offer, and takes the job.

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By standing up for himself, Leonard not only gets a new position at the university, he also learns how much he's valued as a scientist. He might not have gotten what he wanted most, but it led him to a better position.

With just four episodes left, the characters on The Big Bang Theory are taking major leaps in either their professional or personal lives. Leonard's promotion is only the latest in a string of successes for most of the  main characters: Howard and Bernadette now have a family; Sheldon and Amy are in the race for a Nobel Prize; Stuart has become a successful artist; and Raj has finally found love.

Now that Leonard has a new job, this only leaves Penny. Will her husband's new position inspire her to pursue her own dreams? After all, when we first met Penny, her one goal was to become a successful actress. It's not too late; she has four episodes in which to take the leap.

The Big Bang Theory airs Thursdays at 8 pm ET/PT on CBS, and will conclude with an hour-long series finale on May 16. The series stars Jim Parsons, Johnny Galecki, Kaley Cuoco, Mayim Bialik, Kunal Nayyar, Simon Helberg and Melissa Rauch.