Penny: So what's the thanks I get for turning Leonard into quality boyfriend material? I have to tiptoe around his new girlfriend.
Amy: I think you're on.
Bernadette: Oh. That bitch!

Howard: I'm sorry I didn't take you to the airport. I just want you to know I'll never forgive myself for being so selfish. And I promise to keep you close for the rest of my life.
Bernadette: Oh, no, that thing's gonna end up in my bedroom.

Bernadette: Gosh, Amy. I'm sensing a little hostility. Is it maybe because like Sheldon's work, your sex life is also theoretical?

Bernadette: (Shouting from the bathroom) How many times do I have to tell you to replace the toilet paper when it's empty?
Howard: I'm in the middle of something.
Bernadette: So am I!

Penny: Give my friend his stuff back.
Tod Zarnecki: I don't know what you're talking about.
Penny: Well then good news. Today's the day a girl's finally going to touch you in your little special place. *Kicks him in the groin*

Raj: Come on, dude, bros before ... my sister.

Sheldon: I've never said these words before, but good job, Howard.