You might be thinking I'm referring to when two horses don't get along, or two people...nope, I'm talking about when a person picks their poison, versus picks their pleasure...meaning they have chosen a horse that makes life miserable, on the both of them, in one way or the other. Opposites do attract, but make sure you are aware of the consequences (and benefits) of that, before sighing up for a relationship that might last 10, 20, or even 30+ years.
It is something I see fairly frequently in the field; a fiery, determined, bold-as-brass horse and a timid, soft owner/rider. Or an unstarted, snorty colt with a green as grass owner. Or a demonstrative, full-steam-ahead owner teamed up with a timid, shy and sensitive horse... "Eeek", is usually what I say in my mind, because I know I have my work cut out for me to help the pair find some middle ground, when they both are so far apart.
Choosing your opposite personality when it comes to animals, will demand growth on your part... that is to have much success, enjoyment or fulfillment anyway. Unfortunately predicting a personality clash isn't so black and white, that you can figure out just HOW MUCH you are going to have to stretch yourself with a specific individual ahead of time. That wisdom comes with interaction and spending time with that individual in various situations. As a horse trainer, I must be highly adaptable to the individual, and give it whatever it needs to feel successful, but that skill has been developed over my lifetime and from working with 1000's of horses in as many situations. As a non-pro or hobbyist, it is important to know "who" you are, and not get "blind" in the purchasing or adopting process, accidentally biting off more than you can chew, or want to chew for that matter.
Pushing your Horsemanship growth is important, but pushing it so far you are constantly scared/terrified, or constantly upset and aggravated is not worth the pursuit. The animal doesn't have a choice, but we do. I work at convincing people frequently in these situations, that the horse is probably just as miserable in it's own way. Finding a person that enjoys the qualities in the horse that clashes with your personality, and then finding a better suited horse for yourself, it is not about failure as a horseman or being uncaring, it is actually the kindest, wisest thing for you both!
There are a lot of armchair quarterbacks out there that'll give you an opinion that's not worth the time it takes to listen. If you can, whether you are already in a situation with a horse, or during the purchasing process, seek a professional's opinion. Hopefully they can give you quality, objective advice about how much of a stretch or not the relationship would be for the both of you. In the end, to make it as positive an outcome for both you and the horse, #1 know yourself and be honest about it, and #2 trust your intuition...it will rarely let you down.