Some of my favorites:
"We wanted a gray horse, but now he is lighting up and we don't want a WHITE horse. Will trade for another gray."
So you can sell it in 2-5 years?
"Very broke, very ridable, but our other horse is herdsour with him and makes noises when he leaves."
So you're getting rid of him... because then that horse isn't going to make any noise at all.
"Don't really like geldings, want a mare."
I asked why, and she said she didn't like looking at them when they pee... what?
If you branch off into other animals, I REGULARLY see ads where people are selling donkeys because they don't like the noise they make. It's like, why'd you get a donkey, then? You thought they didn't really make noise? I also once saw a mule for sale because it made a "funny" noise, "it isn't like a bray or anything, it just is annoying."
I've also gone to a couple of places to look at horses, and everything seems great... until some little detail slips. Like one horse I looked at it turns out, had hip problems, but it "wasn't noticable"... she walked with a CLEAR limp. Another was "hyper", so they kept it in a stall for a month, and when they let it out, it nearly ran the person over. They explained he was "just happy to see them". Suuure.
I also went looking at a colt once, and the owner said, "He's not broke, but he could be REAL easy!". He then literally JUMPED on the horse, which was bareback and loose in a pasture, and tried riding it. It did NOT go well.