Sex, kinks, political affiliation, age, height, etc.
Swastika tattoos lol.
On a more common note, would take a bit to go for a smoker or stoner. Basically don't see many of my best friends often (even though they're nearby) because I can't stand being in smoky rooms that I can smell from my clothes the day after. Not big on women who "act blonde" either.
My big two are any kind of addiction and any kind of mental health problem. Or history of either. Sounds callous, but when you end up on Prozac, not through anything that's wrong with you, but because you need it to live with the shit your partner throws at you every single day, then you're very much in the wrong relationship. Been there, done that. Avoid. Avoid. Avoid.
They might not be absolute deal breakers. If I developed very strong feelings for someone, then I might be willing to go against my better judgement. But either of these would be reasons for me to keep my distance in the first place, so hopefully it wouldn't happen.
theist or one that depends on faith (belief without evidence) to support a claim in contradiction to verifiable reality
cruel
republican
racist
not intelligent
irresponsible
dishonest
lack of respect and caring for self and/or other animals
I will forgive your question, If you forgive me asking everyone that asks these sorts of questions why would you expect answers and why would you wish them?
no hairy balls and must have a heartbeat, oh and nothing green should be oozing out of them. sorry, I'm just picky like that.