Anyone who says "I'm too jealous for".
I find that if they say that once it's a good sign they have undealt with baggage hiding in there.
I second Ceoli's "don't ask, don't tell" one. If we can't be friend-you don't need to have my husbands cock in you. PERIOD. Likewise-if you can't be friend with him, you have no need to have yours in me or whatever (I'm bi-but you get the picture).
Anyone who sends naked pictures to me before having a few GOOD, SERIOUS INFORMATIVE conversations.
Anyone who says they want a specified dynamic *such as a triad or quad* up front. Sure-I'd LOVE a quad (in a V right now). But that isn't POSSIBLE without RELATIONSHIP and relationships can't be created to meet a design (imho). If a relationship develops (friendship is a relationship in this conversation) the we can see if it will work in the "family" in some way.
People who hate all their ex's.
People who say "(S)he did blah blah blah" when describing why their last relationship ended instead of saying "we or I"....
off the top of my head (too much time on my hands at the moment).
"Love As Thou Wilt"