system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do animals let us domesticate them? / Why can't we domesticate some animals?
gpt
You should read Guns, Germs and Steel by Jared Diamond.  He talks a lot about why certain animals and plants were domesticated and why others weren't.

As far as animals that won't let us domesticate them--some aren't suitable because their panic instinct is so high they aren't dependable.  Zebras can be ridden like horses, but since they are used to being attacked by lions and cheetahs, they will dump you and take off the first time something freaks them out.  They also get mean as they get older and can really injure you with bites and kicks.

Rhinos would be great war animals, but you have to feed them tons and tons of food and when it's mating season, then males will fight to the death, so that would be inconvenient for breeding. 

The Jared Diamond guy has lots of other examples too.