To commemorate The Big Bang Theory series finale, cast members were asked to select their favorite episodes. Johnny Galecki found that the episodes that showed Leonard's emotional evolution and romantic side rose to the top.
Johnny Galecki chooses his favorite Big Bang Theory episodes
The Wheaton Recurrence
Sheldon gets to square off at the bowling alley against nemesis Wil Wheaton. Meanwhile, Leonard's miffed when Penny doesn't respond the way he hoped after saying I love you.
What Johnny said: "It was the very personal moments, such as the character having his heart broken, that permitted us to mature him. That was always exciting as I knew it would be a changed Leonard moving forward. Still Leonard, but that I’d need to consider that he would see things differently."
The Benefactor Factor
After meeting at a fundraising gala, an aged but wealthy, Caltech donor makes Leonard ponder if he's willing to have sex with her to secure another donation.
What Johnny said: "This was probably my favorite memory of a live audience taping. It felt very private. The cameras, crew and audience kind of disappeared in that moment. And that was the moment we used. One take."
The 43 Peculiarity
Howard and Raj try to solve a mystery about Sheldon.
What Johnny said: "I remember talking a lot with Chuck Lorre while we filmed this. He had the great note to play the speech in the tone of a future me giving myself advice."
The Gorilla Dissolution
A trying day at the movie shoot leaves Penny with questions about her life choices, so she decides to act on it; and caring for a bedridden Mrs. Wolowitz proves a challenge for Howard and Bernadette.
What Johnny said: "I found it heartbreakingly sweet Leonard quietly carried a ring for God-knows-how-long. For all of his math and science, Leonard was a diehard romantic sentimentalist. It’s never more evident than in this episode."
The Graduation Transmission
Wolowitz questions his abilities when he and Sheldon can't get a drone to fly. A canceled flight nearly prevents Leonard from giving the commencement address. Raj pits his parents against each other when his father cuts him off financially.
What Johnny said: "I loved working with Jessica Walter. And that Penny saw a side of Leonard she didn’t before know. Or consider."