What part of an inverse tangent approaching an asymptote don't you understand?

A fear of heights is illogical. A fear of falling, on the other hand, is prudent and evolutionary

Sheldon [looking at the women's book in a bookstore]: "Coping with the Death of a Loved One." My condolences
Woman: Thank you
Sheldon: Family or friend?
Woman: Family
Sheldon: Too bad. If it had been a friend, I'm available to fill the void

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

Penny: Leonard isn't the kind of guy I usually go out with.
Sheldon: Leonard isn't the kind of guy anyone usually goes out with

Leonard: I don't think I can go out with [Penny] tonight.
Sheldon: Then don't.
Leonard: Other people would say, "Why not?"
Sheldon: Other people might be interested

Leonard: Why are you learning Chinese?
Sheldon: I believe the Szechuan Palace has been passing off orange chicken as tangerine chicken, and I intend to confront them.
Leonard: If I were you, I'd be more concerned with what they're passing off as chicken

Penny: I was just wondering if I could talk to you. It's about Leonard.
Sheldon: Why me? Why not Koothrappali or Wolowitz?
Penny: Well, Raj can't talk to me unless he is drunk, and Wolowitz is, you know, disgusting

Leonard: Now that I'm actually about to go out with Penny, I'm not excited, I'm nauseous.
Sheldon: Then your meal choice is appropriate. Starch absorbs fluid which reduces the amount of vomit available for violent expulsion

Sheldon: Leonard made it very clear, he doesn't want a party.
Wolowitz: Did someone say party?
Penny: He just doesn't know he wants one because he never had one.
Wolowitz: I suppose that's possible, but for the record I've never had a threesome and yet I still know I want one.
Penny: Howard here's a difference: the possibility exists that Leonard could have a birthday party before hell freezes over.
Wolowitz: Fine, if I do have a threesome you can't be part of it... I'm just kidding. Yes, you can. Can you bring a friend?

Penny: Well, Sheldon you are his friend. Friends give each other presents.
Sheldon: I accept your premise; I reject your conclusion.
Wolowitz [whispers]: Try telling him it's a non-optional social convention.
Penny: What?
Wolowitz: Just do it.
Penny: It's a non-optional social convention.
Sheldon: Ahh, fair enough.
Wolowitz: He came with a manual

Leonard: How did you know my birthday's Saturday?
Penny: I did your horoscope, remember? I was going to do everybody's until Sheldon went on one of his typical psychotic rants.
Sheldon: For the record, that psychotic rant was a concise summation of the research of Bertram Forer, who, in 1948, proved conclusively through meticulously designed experiments that astrology is nothing but pseudoscientific hokum.
Penny: Blah, blah, a typical Taurus

TBBT Quotes

Sheldon [to Kripke]: Also, I am given to understand that your mother is overweight.
Raj: Oh, snap.
Sheldon: Now of course, if that is the result of a glandular condition and not sloth and gluttony then I withdraw that comment.

How is "doable" anything but a compliment?

Wolowitz