Think of it this way.
When looking for a husband/wife, you don't just get on a website with a list of a thousand people looking for a mate- find someone attractive, and go 'oh, he's(or she's) THE ONE' and you go marry them without having even talked to eachother. Or if you did, it wouldn't work out. Why? Because of personality. Way of doing things. Pet peeves. Health. Life style. It all ties together to make you you
and make them them.
The only way to know if you're 'soul mates' is by talking. Getting to know eachother. Finding out as much as you can about eachother.
It's quite the same with a horse. You and your horse are partners, just like a husband and wife are. You have to have meshing personalities. A bullheaded horse isn't going to go well with a timid rider, and a rough and tough rider won't go well with a skittish, low confidence horse.
And you can't tell personality from a picture on a computer.