"He's SO pretty!"
How many times have we heard that in the horse world? I'd say too many... for example:
1) A woman bought a horse simply because, and I quote, "He's so par-r-r-r-r-etty!". The horse in question was a gorgeous tall blue roan, but was very hard-headed and needed a strong rider, who this person was not. The result? Horse wound up rotting in the pasture, never being taken out from one end of the month to the other, and was put up for sale within two months of her buying him. Let it be noted that this woman was not new to horse buying: she had three other horses whom she had also bought for their looks and had trouble riding.
2) BNT routinely bought prospective showhorses online sight unseen basically based off good looks and got burned at least twice: once when the horse arrived she found he had human eyes (sellers managed to hide it in the photos), and the second time when it turned out the horse was much greener than she had been led to believe. (This also falls under the why-buying-a-horse-sight-unseen-is-a-bad-idea category, but that's another issue altogether)
3) The first time horse buyer carving it in stone that the horse they get MUST be a palomino/buckskin/blue roan/cremello/etc.
...and the list goes on.
Let's get one thing straight: excluding conformation, the outside of the horse does not matter. It's what's inside that counts.
I remember when I was looking for a horse for a family member, I asked someone I knew if she had or knew of any horses for sale. She immediately told me that she could find me something if she didn't have it, and her first question was, "What color do you want?"
I told her the horse could be hot pink for all I cared, as long as it had a suitable temperament for someone who was a bit timid and just getting back into riding. The lady seemed a bit mystified by this attitude, and came up with a horse who was "really pretty" but tried to throw his rider on the test ride.
Everyone wants a beautiful horse that everyone else will drool over. It's perfectly understandable and normal, but it becomes trouble when people let it become one of the main criteria in their horse buying ventures, sometimes to the point where they'll pass over a trusty, steady bay for a flighty, spooky palomino.
If you want nothing but a lawn ornament, go ahead and set color or good looks as one of your main criteria. But if you're going to work with and ride the horse, his being pretty is not going to help you when he's being stubborn, buddy or barn sour, refusing to lead, or trying to dominate you.
I'd like to say this wall of text is directed to first time horse buyers, but unfortunately I've met too many people with literally decades of experience owning and/or training horses who buy horses for their looks or color.
Now, if you wanted a flashy Paint to show at APHA breed shows, and got yourself involved with a respectable APHA show barn, odds are you wouldn't have that much trouble getting a nice APHA performance horse through said respectable barn. But unless that's the scenario, instead you're cruising around online classifieds such as Horsetopia for anything below a successful performance horse, you need to keep in mind that, and I repeat myself, excluding conformation, appearance doesn't mean a thing. Sellers use a horse's good looks as a huge selling point, a lot of them actually boost the sale price because the horse is "pretty" or of an unusual or "special" color. But it is no indication of what sort of temperament the animal has, or if you'd want to touch it with a ten foot pole.