Consider dog(s).
If it is a big, active one, maybe even something like a border collie or another sort of dog that only is happy if getting trained, then you must invest time and effort into it as well. Certain dogs depend on being kept busy, else they become almost neurotic. Such dogs will keep you busy in return, too. But you are not as limited with dogs like with having the responsibility for a horse. My parents had dachshounds and collies - that was fun. My grandfather had a band of hunting dogs - that was work.
But you could of course also have a horse and name it Dirt Bike.
