Leonard: What am I supposed to do, pretend I believe something I don't whenever I'm with Penny?
Howard: Hey I'm sure Penny fakes all kinds of things when she's with you.
Leonard: Do me a favor: lean over and put your head right here [in front of a laser he'd been using to fry action figures].
Howard: Let me show you another way to look at this. [Draws a large box on a dry-erase board] Here we have the universe of all women. [Draws one large circle inside the box] These are the ones you want to sleep with. [Draws an equal-size circle slightly intersecting the first] These are the women who believe exactly what you believe. [Draws a very small circle at bottom of the intersection] These are the women who would be willing to sleep with you. Right there at the little triple intersection is your ideal mate. Odds are she's a short physicist with low self-esteem who lives in a government research facility in China.
Leonard: What's your point? In order to keep having a sexual relationship with Penny, I have to give up everything I believe in, my intellectual integrity, the very nature of who I am? I can't do that, Howard.
Howard: I respect that. [takes Leonard's hand and dots his palm with the marker]
Leonard: What is that?
Howard: Your new girlfriend. Have fun tonight.

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