You see that douche over there? The one with a crazy ridiculous haircut, bright pants, or obnoxious shoes? Yeah. He could be one of your new best friends, and even more, a friend for life.
The truth is, strong personalities clash. And they usually clash hard and fast. Almost immediately you can detect if you 'don't like somebody' and before you know it you're passing judgement on someone that a.) probably doesn't deserve it, and b.) someone you don't even know at all. You get that feeling from deep in your subconscious, stirred from a moment of foreign familiarity (not unlike deja vu), and you just can't seem to place your finger on why. That's where the fear/dislike comes from. People don't like what they don't know or can't comprehend.
So. Before you blow someone off for being crude or audacious, remember that if they were your friend you'd probably be all about the fun they're having, and you'd be encouraging it. You never know where your next favorite person can come from. Or how.
Or they could just be a douche... Stay crazy my friends.