First of all, let me say right here, I am not buying a horse. I just like to look and dream (ride once a week at a riding school, very much a novice). No time, insufficient money atm. Right, that's that out the way 
However on the dream front, I sometimes spend a little time browsing horses for sale. If I were looking properly, I'd be looking for a horse who's happy to be ridden in a riding school and perhaps be sane enough to take out of gentle hacks on the farm land round my riding school. I never seem to see horses like this - the ads always talk about how well a horse jumps, what competitions they've done, ready to advance to next level of dressage or whatever.
I think I probably look in the wrong places (i.e. whatever Google throws at me). So, my musing - where are all these lovely sane happy-to-just-ride horses sold? They must be out there, because lots of people must just ride for pleasure rather than enter comps etc. And I ride 3 of them at my riding school (though one of them, I know was bought at a sale, where the YO was bidding against the knacker - best money he's ever spent, he said, as the horse is a lovely chap).
Thanks