Raj: I don't like bugs, okay. They freak me out.
Sheldon: Interesting. You're afraid of insects and women. Ladybugs must render you catatonic.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Stuart: Oh, Sheldon, I'm afraid you couldn't be more wrong.
Sheldon: More wrong? Wrong is an absolute state and not subject to gradation.
Stuart: Of course it is. It's a little wrong to say a tomato is a vegetable, it's very wrong to say it's a suspension bridge.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Sheldon: I feel renewed. I'm ready to deal with any changes that come my way. [sees Penny] Your hair is different. You changed your hair. I can't take this. I'm out.

Bernadette: How you doing, Howie? You feeling a little better?
Howard: Oh, a lot better, thanks. One sec. Listen close, I don't have a lot of time. I need you to go to my house. In my bedroom, you'll find a model rocket. I want you to take it and bring it back to your place.
Bernadette: Okay.
Howard: Step two, build a version roughly fourteen stories high. Fill it full of rocket fuel and come get me. I'll leave the door unlocked.
Bernadette: Howie, honey, maybe you should talk to someone, let them know you're having a little anxiety.
Howard: No, no, I'm fine. No anxiety. We should probably talk in code. From now on, frog is me, sandwich means you and lemon means rocket. So, come on, sandwich, build me a lemon 'cause froggy wants to come home.

Mary Cooper: Thank you, God, for the food we are about to receive and for the nourishment of our bodies and bless the hands that prepared it. Amen.
Sheldon: Given that your hands prepared it, isn't that a little self-serving?
Mary Cooper: You start changing the words to the prayers, next thing you know, you're in a church with a guitar.

Bernadette: See? You're doing great.
Penny: Yeah. Mediocre actress, great drug pusher. Who knew?