After 12 years, The Big Bang Theory, the longest multi-camera sitcom in the history of American television, is saying goodbye.

I remember starting to watch it back in 2007 with no expectations, since I had no prior knowledge what is called the “geek culture”: Star Wars, Star Trek, Dungeons and Dragons, among many other references to movies, games, TV shows, and comic book characters that I had no familiarity with. Yet, I loved it from the beginning!

It started with Penny (Kaley Cuoco) moving in across the hall from Sheldon Cooper (Jim Parsons) and Leonard Hofstadter (Johnny Galecki), two physicists who had no social skills whatsoever. Their two friends Rajesh Koothrappali (Kunal Nayyar) and Howard Wolowitz (Simon Helberg) were even worse: Raj suffered from selective mutism, which prevented him from talking to a woman and Howard would try to hit on as many women as he possible could.

Over the course of twelve seasons, they’ve come a long way! Penny, whose family name remains unknown, married Leonard; Raj can now talk to women without help from alcohol; Howard went to space (!!), married Bernadette (Melissa Rouach), and had 2 children; and Sheldon finally found someone who can stand him (most of the time): Amy (Mayim Bialik)!

My favorite character has to be Sheldon. He manages to be infuriating and extremely funny at the same time. His roommate agreements, his spot on the couch, his lullaby for when he’s sick (“soft kitty/warm kitty/ little ball of fur/ happy kitty/ sleepy kitty/ pur, pur, pur”), his “Bazingas“, his “Fun With Flags“, and everything else, are simply hilarious.

The show also managed to have a huge number of guests appearances, both as themselves (Bill Gates, Stephen Hawking, Will Wheaton, Stan Lee, etc.) and as playing other characters (Laurie Metcalf, Christine Baranski, Bob Newhart, among others).

It is hard to choose the best episodes over 12 seasons, but I gave it a try and selected my top 12 (warning: spoilers ahead!):

12 – The Imitation Perturbation (Season 12)

Halloween episodes were always special, since the characters really enjoy the holiday and dress up in different costumes. This year, Howard dresses up as Sheldon, and one thing I’ve always loved are Simon Helberg’s impersonations of others (either famous people or his fellow cast members). This time, though, we get to see Sheldon impersonating Howard as a way to get back at him!

11 – The Bow Tie Asymmetry (Season 11)

Amy and Sheldon finally get married! That would be enough for this episode to be on my list! But their wedding is even more special since it’s officiated by Mark Hamill himself! I am not a Star Wars fan, but I know how much these characters like him, so it was nice to see them getting married with him there.

10 – The Convergence Convergence (Season 9)

Penny and Leonard decide to get re-married in front of their friends and family, which brings some family members together and cause tension. The best part of this episode is seeing the interaction among the guest starts, specially Laurie Metcalf and Christine Baranski.

9 – The Hawking Excitation (Season 5)

Howard is working with Professor Hawking and Sheldon desperately wants to meet him. Howard, then, takes advantage of the situation and makes Sheldon do a series of tasks to finally see him. The whole episode is pretty funny, but it was sweet seeing Sheldon with Prof. Hawking (and realizing there was a mistake in his math).

8 – The Bat Jar Conjecture (Season 1)

When the group is competing at a Physics Bowl, they decide to exclude Sheldon due to his obnoxious behavior. He, then, decides to form a team himself. I love this episode for many reasons, but one of them is that Mayim Bialik is mentioned, even before joining the cast as Amy! When trying to find a replacement for Sheldon, Raj suggests “the actress who played TV’s Blossom”, since she has a PhD in neuroscience. Mayim Bialik joins the show in the Season 3 finale and becomes a regular cast member in Season 4. I also love the ending, when Penny tests Sheldon and Leonard’s knowledge of pop culture!

7 – The Raiders Minimization (Season 7)

I was never a huge fan of Indiana Jones and the Raiders of the Lost Ark, so I had never really thought about the plot that much. Maybe that’s why I found this episode so funny: Amy points out all the problems the movie has to Sheldon and he refuses to have it destroyed like that.

6 – The Creepy Candy Coating Corollary (Season 3)

Prior to this episode, I had no knowledge of who Will Wheaton was – I really never watched Star Trek. But this was a fun way of finding out about him: Sheldon hates him for something that happened years ago and wants revenge! 

5 – The Re-Entry Minimization (Season 6)

Howard comes back from space and thinks everyone will be anxiously waiting for him, but everyone else is already busy. The best part is the game night taking place at Sheldon and Leonard’s apartment – Penny and Amy team up against Sheldon and Leonard in a series of games, including a pie-eating contest!

4 – The Luminous Fish Effect (Season 1)

Sheldon gets fired and, for the first time in a while, has a lot of free time. He starts all sort of different hobbies, which makes Leonard worry about him and call his mom, played by Laurie Metcalf!

3 – The Bath Item Gift Hypothesis (Season 2)

Sheldon hates being touched or touch other people. That is why the highlight of the episode happens when he finds the courage to hug Penny for the first time to thank her for a Christmas gift. 

2 – The Barbarian Sublimation (Season 2)

Penny goes through a personal crisis and finds solace in online gaming – perhaps too much! Her scenes with Sheldon are always hilarious, especially in the early seasons, so this episode is perfect for that. Another great moment in the episode happens in the cafeteria, when Sheldon is trying to find someone to date Penny to get her mind off the game.

1 – The Scavenger Vortex (Season 7)

Raj decides to organize a scavenger hunt and the result is simply hilarious. It’s the first time Amy and Howard actually get to spend time together and they find out their mutual love for Neil Diamond.

I honestly don’t know how they’ll end their stories – probably not in any major life change. I guess they’ll just keep living their lives. But it has been great to follow their journeys for 12 years!

The series finale airs on Thursday, May 16, on CBS.