I think this is the major, common mistake made. I believe that temperament is the most important thing – a willing attitude, honesty, kindness, a cooperative nature are qualities that are sometimes undervalued, IMO. I see riders not only being scared, but spending so much time (years!) and effort on a non-match. And there are horse/rider combinations who are not a fit due to rider fitness/athleticism (or lack therof), or the rider simply not having the time/energy/wherewithal to put into that particular horse (or themselves), when perhaps the pairing could have worked out in different circumstances.
Not to mention that situations change over time – for instance, my husband has always preferred a horse with a bit of an edge, the motor running, a quite forward horse (not a bolter or difficult personality, however), but he’s admitted to me that, at this latter time of life, he’s a little more interested in a little less forward ride. Time eventually catches up with us all!
When I say kind and cooperative, I don’t mean deadhead, either. Rather, a responsive horse that listens, pays attention, one which allows the rider the gift of that split second before things go sideways. I have no problem with forward – haven’t owned anything without forward – and I like sensitive. Forward and hot aren’t the same thing (to me), either, nor are forward and challenging, or hot and difficult, or sensitive and hot.
I’ve owned horses that were real thinkers/anticipators, where the riding challenge was to constantly think at least two or three steps ahead, and never repeat a pattern/sequence/combination, but that’s a sign of an intelligent, cooperating horse that is paying attention and wants to please - a horse that is in the game. I’ve owned very quick horses with lightning reflexes, which didn’t bother me – like I said, I don’t mean deadhead.
But I’ve never owned/bred a horse that didn’t want to listen, that didn’t have a try in it, that had a dirty stop or buck or spook, or was continually mentally exhausting, that lacked common sense or self-preservation. Sterling character has been of paramount importance to me when breeding my own stock, or when purchasing young prospects.
I do try to never just check out when riding - to always be present in the moment – even when hacking. I have to admit that I’ve come off only a handful of times in over a half-century of riding (including always starting my own horses, jumping back in the days when we ammies did big courses, polo, etc.), and have never broken anything, which surely colors my opinion. I have friends who have been very seriously injured riding (broken back, TBI, etc.), and I can well imagine how that could shake someone’s confidence, including my own, leading to a frightened, over-horsed rider.