finding the right horse is like any other relationship, some aspects need to match, others need to be opposites. You probably don't want a timid horse with a timid rider, they'd never get anywhere if the horse spooks at a new sight and the rider is nervous about the horse spooking; but active go-get-'er personalities do well together because both horse a rider want to be going and trying new things. A lazy rider probably doesn't want to work to get a lazy horse moving.
I prefer active, bold horses, which is pretty similar to my personality, but I don't want to argue with a horse over dominance. But it also depends on what you want to be doing with the horse. I've been up on every horse at my current instructor's place, and I actually prefer the lazy, grouchy pony. He does not want to go fast or collect and he makes darn sure you know it, but when he does finally decide to give in he moves beautifully, will jump anything, and really, he makes me work for it. I don't take riding lessons to sit up on a push-button pony and just plop around a few fences, I go to make myself a better rider and the more the horse makes me work for it, the more I learn exactly what I need to do to get the results I want. But I wouldn't want to own a horse that makes me work that hard all of the time.
*As a side note, he is a stallion. 20yo, under 14hh, perfectly well behaved, sorta. He would never "really" do something wrong, but when working in the arena with a pretty bay mare, he tries to speed up a bit when behind her, slow down when passing or in front of her, and takes a lot more leg to get a smooth turn away from her. He is not a terror of a stallion and is probably the best behaved stallion I have ever been around, but him simply being a stallion just takes more work and thought from the rider (watching where mares are in the ring, if a mare has a less experienced rider, mare is in heat, etc) than a gelding or a mare. They can make wonderful mounts, but *usually* a gelding or mare will make a better riding mount and trail partner than an equally trained stallion.