We all have our moments...those times that we wish we could erase or at least forget about in which we have acted like total asses. It happens and usually it's forgivable. However, there are those instances where a douchebag move is and should be a dealbreaker.
1. Telling lies or other "non-truths"
Tell no lies. Just don't. Using the excuse that people don't like to hear the truth or aren't ready for the truth or some other nonsense like that is just that, nonsense. Of course there are times when the truth is something that we don't want hear and it makes us angry or sad, but that doesn't mean most reasonable people don't appreciate it - even if only in retrospect. Telling the truth means providing other people with accurate information from which to make decisions. When you lie you essentially taking another's ability to make an informed decision about you, that's no good...actually, it's fraud.
2. Fighting unfairly
Cardinal rule of interpersonal relationships should be to always fight fairly. There will always be disagreements and maybe even fighting, but you gotta be grown-up enough to fight on the up-and-up. Which means...no name calling, no lying (see above), no using the words "always" and "never." There could be more said here, but I'll keep it basic and leave it at that.
3. Being sexist
Not cute = Dudes, who are otherwise progressive and reasonable, caught in the act of telling sexist jokes, hating on women as a group, blaming women for their own interpersonal pathologies, etc... Sexist behavior doesn't make you look like a "man," it makes you look ignorant, pathetic, whiny and just basically like a sexually frustrated guy who can't get any. Lay off the women, they are not your problem...you are.
4. Being decidedly not-chivalrous
No one needs anyone to wisk them away on a white horse, but that doesn't give you a free pass at common decency. Give up your seat on the
Anything to add?