Dirty bathrooms are my pet peeve. If I go to a man's place and have to use the bathroom you better believe while I'm in there I'm checkin' the ring around the toilet and the ring around the tub!
It REALLY pisses me off when I go into a grown man's house (roommate or not) and his tub is varying shades of gray and brown! What the hell!? Do you not see the change in color? Was your tub not white when you moved in? Oh and please don't get me started on the toilet. . . okay I'm started! If I can tell how bad your aim is as soon as I walk in your bathroom, it's definitely a deal breaker. Whatever happened to flushing for good measure? You knew I was coming over, why didn't you get rid of those traces of last night's dinner floating around in there?? Too much?? Okay, I apologize. I just needed to get the point across. I digress.
Anyway, all you not-so-gentle-men, please don't wonder why I left and didn't call you the next day. Just check your outhouse for the answer.