1. Cheating. That's the number 1, don't ever cheat on me in anyway, under any circumstance. I will refuse to associate with you from that point onwards.
2. Naive/"Police Officers are Superheroes and the Law in their weapon!" people. I can't stand those sorts of people, and if I was ever to 'meet' someone like that, most of my friends would leave me at that stage as well.
Otherwise, I'm not too fussed.
Looking at the OP's post, I'm not sure what to say.
I couldn't care if you gamed, and if you gamed 'too much' than we wouldn't be able to hold a relationship anyway.
Mates have pulled knives on me as a joke, so I really couldn't care if you tried to punch me - so long as you expect retaliation.
I smoke occasionally, with a good cigar.
Musical tastes don't affect me unless they force me to listen to it, if you stole then the relationship would never get off the ground in the first place, so I'm not fussed about that one, and massive weight gain - eh, you'll run yourself into the ground anyway. So either you'll destroy yourself or I'll get fed up with you. Though that one is an eventual thing, not directly a 'deal breaker'.
STD's nd shit, so long as you're clean when we get together, not a problem.