I think too often we're taught not to trust our intuition, when we really should be trusting it. No, there doesn't have to be an articulable reason you don't like someone. So long as you remain professional, you don't have to like everyone you come across.
I find that when someone just rubs me the wrong way from the beginning, they (almost) always wind up doing something later to confirm their douchecanoe status. I never act on it, but my intuition is usually pretty spot-on.