Raj: I'm always attracted to women I can't have. I do it all the time. I did the same thing with the two of you.
Amy: The two of them? I don't understand.
Raj: Well, uh, there was a time when I had a thing for Penny, and I thought she was into me, too, because she got drunk and naked and climbed into bed with me. But apparently I misread those signals.
Amy: And you liked Bernadette also?
Raj: That was before Penny. I make it a rule to only fall for one of my friends' girlfriends at a time. I'm very old-fashioned that way.