Hair.
That is, other people's hair. That is, the hair of other people lying around, in drains, on my coat, on the internets, in commercials, drawn into my favorite cartoon. I've never dry heaved at a commercial until Anthony Sullivan began hocking the Turbo Snake on late night tv. I've never come closer to turning off an episode of The Venture Brothers than when Dean picks up and plays with a hair clog from the shower.
In the past, if someone else's hair got on me, I would freak out and look away while making someone else remove it from me. Occasionally, this still happens, but years of working in retail where far more disgusting things (like cash) are handled on a daily basis kind of desensitized me to at least that. But I have a very strong visual/visceral connection, so when I see an image of hair falling to the floor while a guy sits in a barbers chair in an H&R Block commercial and asks if a hair cut is a "job hunting expense", I just about lose my shit. Yeah... it's a problem.
This all started probably when I was 9 or so, and my sister's long black hair was everywhere. Vacuuming wasn't yet part of my chores, but if I had known this would reduce the amount of hair that was, literally, everywhere, I would have taken up the habit a lot sooner. Needless to say, a big deal was made about the mess. Somehow, I internalized this and began avoiding hair. Then, of course, there were all of my friends who had long, frizzy hair in junior high and high school -- I, personally, cut my hair very short at 12 and later at 15, and since haven't ever had it longer than my chin; the shortness, combined with the color (RED!) helps me to not freak out over my own hair.
Of course, all of this is made even more idiosyncratic because I live with a dog and human who each have full heads and backs of hair. Pugs shed more than just about any creature this side of Alpha Centauri; the Schmoogie, thankfully, not so much. And I'm lucky enough that having to clean hair clogs out of drains is a thing of the past -- living with Kia, as bad as that was on its own, was made infinitely worse by the fact that she never bothered to clean anything, let alone hair from the shower drain... I once had to dig a giant, dishwater-blonde hair clog out with a chopstick while wearing nitrile gloves.
Don't mistake me, I don't mind hair that maintains some delusion of continued life -- I suppose you could say that my aversion to hair is similar to the aversion of others to corpses -- and I'm certainly no germaphone germaphobe, I just don't like looking at, touching, being touched by, or having to acknowledge the existence of discarded strands or clumps of hair. (Actually, I don't like being touched by living hair either -- if another girl in a club swings her hair around and touches me with it, I will throw down. You assault me with your uncontrollable hair, I will assault you with my fists. That's how irrational I am about this!)
So, I don't know, would people please stop putting little clumps of hair on the damn tv. It's really starting to get under my skin... ew. Now I'm gonna have nightmares about hair under my skin. Great. Thanks usually harmless colloquialism.