Yes, a lot of it's cultural (many cultures eat feet and heads, for instance, while I'm sure most Americans would be grossed out by that) but I'm talking about the ones to which you yourself have an unreasonable response - you know you're being irrational, but you just can't help retch a little.
We butterflied a chicken and roasted it for dinner the other night. The oven rack was too high so the top got cooked but the meat closer to the bone was still quite pink, so we popped the undercooked stuff into the fridge to cook it up in a stir-fry the next night. We feed our dog raw food, so I butcher raw chicken on a daily basis, but somehow, ripping away the half-cooked flesh from the bones was SO much more revolting. I almost had to wait for my husband to get home from work to finish the job as it was making me sick to my stomach. Spam is the other one for me. I literally got sick once because a roommate watched a Dateline special on a man who ate nothing but spam for a year - seeing his pancake-shaped breakfast spam and his turkey-shaped Thanksgiving spam sent me racing to the bathroom to retch. Seeing spam advertised at the Burger King's in Hawai'i instantaneously made me lose my appetite on the way to our restaurant.
Don't get me wrong - I'm not judging someone else loving Spam. I have no idea why I have such a visceral reaction. I've never even tried the stuff! But it got me curious as to what other people's instant turn-offs were. Anyone else out there as crazy as I am?