I have never met a guy who self-describes as "nice," whether it's in a profile or real life, who is that. On the contrary, he invariably turns out to be a douchebag. I've always found this to be fascinating. It's as if the desire to be nice has somehow warped his interior mirror to such a degree that he believes that his the sum of deliberate actions, which appear to be cover-ups for the little monster he really is, make him into this "nice guy."
The same goes with "sane" and "normal." I know I am neither; in fact, I am a complete nutter and about as abnormal as I can possibly be, and it's not willful, I just have a pathological fear of appearing ordinary. As I say in my profile, I'm the poster child for ENTP personality type.
To me, anyone who would want to be normal is absolutely insane. The communal perception of what normal should be is forever changing, so how can it possibly be real in any objective sense? Adhering to the common illusion of normalcy, sane-ness, niceness is far crazier than anything I can conjure up, so I run a mile when I read or hear adjectives like that.
It was only when the guy I'm currently dating described himself as a weirdo, I breathed a sigh of relief and relaxed into the prospect of an LTR.