Sheldon: Don't worry. I will remain the same down to earth, humble Joe I've always been.
Leonard: Good to know.
Sheldon: Now give me that cookie, I discovered an element.

Sheldon: Careful, Amy. The friend of the enemy's girlfriend is my enemy.
Amy: Really?
Sheldon: You're either with me or against me.
Amy: You wanna take the bus to work?
Sheldon: Maybe there's a third option.

Sheldon: I am a grown man. I am a professional scientist. And I currently occupy the moral high ground.
Mary: Go to your room.
Sheldon: But I occupy the moral high ground.
Mary: Go to your room.
Sheldon: But I'm a professional scientist.
Mary: Go to your room!
Sheldon: *Backs away to his room* I'm a grown man.

Bernadette: (Shouting at another driver) Your kid might be a honor student but you're a moron!

Amy: (About Sheldon) Why do I even try?
Bernadette: I'm going to fix this right now.
Howard: Okay, but just make it look like an accident.

Sheldon: I made a new friend who likes trains as much as I do, I kissed Amy on the lips, and the conductor played his banjo for me.

Amy: Did you hold the baby?
Sheldon: I did.
Amy: And how did it make you feel?
Sheldon: Looking into the blank, innocent eyes of a creature that couldn't begin to comprehend anything I was saying ... basically another day at the office.

Penny: You know if we did a shot every time they said something embarassing, this would be one hell of a drinking game.
Amy: Little early for alcohol, isn't it?
Sheldon: (On the radio) You know, I don't just say smart things about science, I also yodel. *Yodelling*
Amy: I'll get the vodka.

Raj: I don't have (Valentine's) plans, which is why I booked time on the big telescope that night.
Amy: An evening looking at the stars, that's still kinda romantic.
Raj: Except I'd be alone.
Amy: I'm trying to put lipstick on a pig here. Work with me.

Howard: It was an hour ago, Sheldon. A Jew sits in front of a house in Texas for that long, for sale signs start to go up.

Sheldon: What are the sleeping arrangements? We've only been dating for three years. If we were to share a room people might talk.

Leonard: I get that you feel bad about all the attention, but still what you did is amazing. We're really proud of you.
Amy: I'm not.
Sheldon: You're not?
Amy: Sheldon, I've been thinking about it and you're right. You don't deserve any credit. All you did was misread some numbers on a table. A very easy table, too. Honestly, I'm embarrassed for you.
Sheldon: That's the most romantic thing I've ever heard.
Penny: Damn it, everyone's better at this than me.
Sheldon: Congratulations, Dr. Fowler. You just made the fort.

Raj: You know, many people believe home births are better because the mother's in a warm, comfortable environment where she can be nurtured by loved ones.
Sheldon: And turn the bedroom floor into an amniotic slip 'n slide.

Howard: The man impersonating a bear would like you to know that, "Only you can prevent forest fires."
Raj: I don't get it.
Howard: You didn't have Smokey the Bear in India?
Raj: No. Was he anything like Munmun the Mongoose? He taught us not to play with cobras.
Howard: You had to be taught not to play with cobras?
Raj: You had to be taught not to burn down the forest?

Raj: In the last hour 162 people have read our profiles. How many of them have sent us messages?
Stuart: Combined?
Raj: Yes.
Stuart: Zero.