Sheldon: Leonard, maybe you'd like to go with them to meet girls.
Leonard: Why would I be interested? I have Penny.
Sheldon: Yeah, for now. But that woman has a death wish, Leonard. She talks to strangers, she pets unfamiliar dogs, and it is ridiculously easy to break into her apartment. If I were you, I'd get a back-up.

Amy: You slept with him?
Penny: I didn't know what else to do. He had those big, sad eyes.
Bernadette: Oh, sure, you had no choice.

Leonard: Sheldon, you are not in charge.
Sheldon: That's mighty sassy for a man with a roommate performance review around the corner.

Sheldon: How can she not be sure how she feels? You know, when I have a feeling, I know it. Trains? Love them. Swordfish. I love them, too. They're fish with a sword for a nose.

Sheldon: FYI, secret keeping? Hate it. Hand-holding? Not a fan. Hammerhead shark? I love that thing. Yeah, it's another fish with a tool on its head.

Sheldon: There's something I need to tell you.
Leonard: Okay.
Sheldon: I can't tell you.
Leonard: Why?
Sheldon: I can't tell you why I can't tell you. So I guess there's two things I can't tell you.
Leonard: I wish there were more.

Leonard: Okay, I think I understand.
Sheldon: You do?
Leonard: The guy who seems like an emotionless robot is you, but your relationship with Amy is causing you to transform into a red-blooded man with sexual desires.
Sheldon: That is literally the stupidest thing I've ever heard.

Penny: Ooh, one gravy boat.
Amy: That's from Sheldon. He told me he had it engraved.
Bernadette: In the event of divorce, please return to Sheldon Cooper.
Penny: One inappropriate, yet I wish I thought of that, gravy boat.

Amy: When I get married, I'm going to register at the UCLA Cadaver Lab.
Penny: Eww, why?
Amy: 'cause I've always wanted a whole human skeleton and they are really spendy.

Penny: I'm not unhappy at all. It's just, I don't know, I've been in love before, but it felt different. But maybe this is a new, better, boring kind of love. Do you ever feel that way about Howard?
Bernadette: Oh, that's not really a fair comparison. I'm basically married to a sexy Buzz Lightyear.

Penny: Amy, you?
Amy: Can't help ya, kid. Whenever I'm around Sheldon, I feel like my loins are on fire. In the good way. Not the urinary tract infection way.

Howard: You're out of your mind, Sheldon.
Sheldon: That's a negative. My mother had me tested. Over.

Leonard: It's like when I started doing chin-ups. I didn't want you to see until I could do one. FYI, really close.

Raj: I think the next time I have to speak to a call center in India, I'm going to try use an American accent.
Howard: Why?
Raj: Because when I use my regular voice, I feel like I'm making fun of them.

Sheldon: It's been three days. Why hasn't Stephen Hawking played a word?
Raj: The guy's a genius. Maybe you weren't challenging enough for him?
Sheldon: Not challenging? I was humiliating the man. I was thinking of writing a book called A Brief History of the Time I Made Stephen Hawking Cry Like a Little Girl.
Howard: There's the problem. You can't beat Hawking like that. He hates to lose. Everyone knows the guy's a big baby. I mean, forget the wheelchair, he should be in a stroller.