Insincerity, phoniness, hypocrisy/whatever. Some of the most interesting people I've ever known (and worked with) have been fucked-up assholes. But we can do business (and actually enjoy each other's company) because the cards are on the table. If I don't read them right, hey, that one's on me. At least they have a code, and at least they live by it. It's the backstabbing, two-faced, never-admit-to-a-lie-even-when-you-catch-'em-dead-to-rights motherfuckers who I have no patience for.
Be upfront about who and what you are, even if it's an asshole, that's what I prefer.