Penny: I give up. He's impossible.
Sheldon: I can't be impossible; I exist. I think what you meant to say is, 'I give up; he's improbable'.

Sheldon: You know, I've always wanted to go to a goth nightclub.
Howard: Really?
Sheldon: Bazinga! You never see any of my practical jokes coming, do you?

Leonard: I'm just saying, you catch more flies with honey than with vinegar.
Sheldon: You catch even more with manure, what's your point?

Leonard: I know what you're doing.
Sheldon: You do?
Leonard: You're using chocolate as a positive reinforcement for what you consider is a correct behavior!
Sheldon: Very good. Chocolate?

Sheldon: Penny, while I subscribe to the "Many Worlds" theory which posits the existence of an infinite number of Sheldons in an infinite number of universes, I assure you that in none of them am I dancing.
Penny: Are you fun in any of them?
Sheldon: The math would suggest that in a few I'm a clown made of candy. But I don't dance.

Sheldon: Interesting. Sex works even better than chocolate to modify behavior. I wonder if anyone else has stumbled onto that.

Girl: What are you gonna get, Raj?
Raj: With my luck, hepatitis.

Leonard: Okay, I know what you're doing.
Sheldon: Really?
Leonard: Yes, you're using chocolates as positive reinforcement for what you consider correct behavior.
Sheldon: Very good. Chocolate?
Leonard: No, I don't want any chocolate! Sheldon, you can't train my girlfriend like a lab rat.
Sheldon: Actually, it turns out I can.

Leonard: They're gonna get beaten up at that club.
Penny: They're gonna get beaten up at Walgreens.

Penny: What's this cartoon called again?
Leonard: Oshikuru: Demon Samurai.
Sheldon: And it's not a cartoon, it's anime.

Sheldon: That does smell good, too bad it's Monday.

Leonard: Sheldon, you need to find a better way of dealing with Penny.
Sheldon: What am I supposed to do? Eat French Toast on a Monday? Now that would be impossible.

Wolowitz: They're called tattoo sleeves. Put them on, have freaky sex with some freaky girl with her business pierced, take them off, and I can still be buried in a Jewish cemetery.

Wolowitz: Yes, she's pushy, and yes, he's whipped, but that's not the expression.

Penny: Ok, who wants syrup & who wants powdered sugar?
Sheldon: I want oatmeal.
Penny: Well, I want a boyfriend whose roommate isn't a big pain in the ass.
Sheldon: I'm sure that will happen soon enough.

Penny: Oh man, did the KISS Army repeal "Don't Ask, Don't Tell"?

Penny: I think we'll pass.
Howard: Oh, is the Mrs speaking for the couple now?
Leonard: In this case, you bet she is.

Leonard: No, her bed kind of ... broke.
Sheldon: That doesn't seem likely. Her bed's of sturdy construction. Even the addition
of a second normal size human being wouldn't cause a structural failure, much less a homunculus such as yourself.
Penny: A homunculus?
Leonard: Perfectly formed miniature human being.

Penny: Okay, so Kim, the night manager, went on maternity leave, and her husband's name is Sandy, right? So get this, her replacement is a woman named Sandy whose husband's name is Kim.
Leonard: Wow!
Penny: I know. What are the odds?
Sheldon: Easily calculable. We begin by identifying the set of married couples with unisex names. We then eliminate those unqualified for restaurant work: the aged, the imprisoned and the limbless, for example. Next we look at-
Leonard: Sheldon! It's an amazing coincidence, can we leave it at that?
Sheldon: I'm sorry. Ooh, Penny, it's as if the Cheesecake Factory is run by witches.

Sheldon: Well, I'm going to make some warm milk and then turn in. I trust if you two are planning in engaging in amorous activities, you'll keep the decibel level to a minimum.

Raj: Are you seriously going to deface your body just for the possibility you could have cheap sex with a strange girl you met in a bar?
Howard: Uh, yeah!
Raj: What is your mother going to say?
Howard: She's not going to see it. She takes my temperature orally now.

Sheldon: Oh, come on, you can't tell me that you're not intrigued about the possibility of building a better girlfriend.
Leonard: I'm not. And Penny's qualities, both good and bad, are what make her who she is.
Sheldon: You mean, like that high-pitched, irritating laugh?
Leonard: Yes.
Sheldon You wouldn't prefer a throaty chuckle?
Leonard: You're not changing how Penny laughs.
Sheldon: No, that would be incongruous, I was going to lower the whole voice to a more pleasing register.

Sheldon: You know, using positive reinforcement techniques, I could train that behavior out of her in a week.
Leonard: No.
Sheldon: If you let me use negative reinforcement, I can get it done before we go to bed.
Leonard: You're not squirting her in the face with water.
Sheldon: No, of course not. Were talking very mild electric shocks. No tissue damage whatsoever.

Leonard: What could she possibly be talking about for so long?
Sheldon: Obviously, waitressing at the Cheesecake Factory is a complex socioeconomic activity, that requires a great deal of analysis and planning. Bazinga!

Bethany: No, I meant what do you do for jobs?
Raj: Oh, we're scientists.
Howard: Yeah, you know, the dark sciences.
Bethany: What are the dark sciences?
Raj: Well, I am an astrophysicist and a lot of that takes place at night. When there are vampires and miscellaneous un-dead out and about.
Howard: Oy vey.

Bethany: So what do you guys do?
Howard: Oh, you know, goth stuff. Goth magazines, goth music.
Raj: Goth food.
Sarah: What's goth food?
Raj: Uh ... blackened salmon?

Sheldon: I'm just tweaking her personality, sanding off the rough edges if you will.
Leonard: No, you're not sanding Penny.
Sheldon: Are you saying that I'm forbidden from applying a harmless, scientifically valid protocol that will make our lives better?
Leonard: Yes, you're forbidden.
Sheldon: (Squirts Leonard with a water spray) Bad Leonard!

Sheldon: There's just no pleasing you, is there, Leonard? You weren't happy with my previous approach to dealing with her, so I decided to employ operant conditioning techniques, building on the work of Thorndike and B.F. Skinner. By this time next week, I believe I can have her jumping out of a pool, balancing a beach ball on her nose.
Leonard: No, this has to stop now.
Sheldon: I'm not suggesting we really make her jump out of a pool. I thought the Bazinga! was implied.

Raj: Do either of you ladies enjoy the novels of John Grisham?

Raj: Light beers? Well, wikiHow about that?

Raj: I think we're fitting in quite nicely.
Howard: It'd help if you weren't drinking light beer.
Raj: Oh, what's so Gothic about vodka and cranberry juice?
Howard: Hello, it looks like blood. Did you even read the wikiHow link I sent you on being goth?
Raj: No, I'm behind on my wiki reading. I'm kind of on a John Grisham kick right now.
Howard: What?
Raj: Well, I finished reading The Pelican Brief and loved it so much, I dived right into The Client. He was a lawyer himself so his novels are accurate as well as entertaining.

Leonard: What was that?
Sheldon: You said be nice to Penny. I believe offering chocolate to someone falls within the definition of nice.
Leonard: It does. But in my experience, you don't.
Sheldon: There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.
Leonard: Yeah. Yeah, now that's you, obnoxious and insufferable.

Sheldon: Look, Leonard, Penny made French toast.
Leonard: Sorry. I haven't given her your schedule yet.
Sheldon: It's an iCal download, she can put it right in her phone. And I thought we agreed that you'd have your conjugal visits in her apartment.
Leonard: We did, but there were extenuating circumstances.
Sheldon: I see. Did her abysmal housekeeping skills finally trump her perkiness?

Penny: All right, want some French toast?
Sheldon: It's Oatmeal Day.
Penny: Tell you what, next French Toast Day, I will make you oatmeal.
Sheldon: Dear Lord, are you still going to be here on French Toast Day?

Sheldon: There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy.