Yes, there are some things that still make me cringe despite 2 years of surgery residency. Watching someone vomit still makes me walk in the opposite direction, heavy body filth and the accompanying odor, as well as fresh stool- ugggh. I've learned to tolerate almost anything as long as I breathe through my mouth.
As for fainting in the OR, sometimes you may have not had anything to eat/drink in several hours, you may be sick, so it may get to you, especially on the cases where you are standing there retracting. I was on a very busy service, working many hours, hadn't had anything to drink in >10 hours when I went down while retracting one day last summer. It's also happened to some of guys bigger and tougher than me as well- sometimes you're sick or worn and it hits you. I've learned to carry things to drink and take something small to eat (even if I don't have time to sit down) and have done pretty well since.