Amy: I'm not sleeping on the couch 'cause you don't know what's private and what's not.
Sheldon: This isn't fair. You've discussed aspects of our physical relationship with Penny.
Amy: That's different! She's a close friend, not the lady in the cafeteria who cuts the crust off your sandwiches!
Sheldon: That lady has a name. I don't know what it is, but one time, I accidentally called her "Mom".

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.

Sheldon: Why are you crying?
Penny: Because I'm stupid.
Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.

Amy: What is this?
Sheldon: I'm mapping basic topics of conversation and with whom they can be discussed.
I call these circles "Zones of Privacy". Don't Google that unless you want to see pictures of people's genitals.

Bert: I met her on G-Harmony. That's a Web site for geologists to find love.
Amy: That's a real thing?
Bert: Yeah. Their slogan is "We're all about dating and not the carbon-14 kind".

Bert: Hey. Looks like I got stood up, so I'm gonna head out.
Amy: Oh, no. Are you sure you don't want to give her a few more minutes?
Bert: Nah, G-Harmony recommends after two hours, it's time to cut bait.