Do you think that every horse comes to teach you something? As is often the case, I have got two ponies that I am working with at the moment with the very same message. Both are busy busy busy on the ground, demand attention, bite (or used to), seemingly agitated, a little too humanised. You'd think that these horses, used to moving humans around and taking the leadership role when there is a vacancy, would have some very clear ideas about work. Having demanded to be waited on, hoof, foot and fetlock (which is not a moral decision on their part - it just works), you'd think that they wouldn't have any work ethic at all . However, in both cases they absolutely thrive on work, thrive on change, thrive on progression. It's as if, having entered the world of humans, possibly been over-handled, they want to know more. Rye, like the robot Short Circuit, shouts "more input, need more input" the moment we bring him in. On the ground he grows calmer every day, the biting is far less, he stands still and he lets things happen so that we can get on with work and find out what's next. Max is the same.
If you spend a lot of time entertaining a horse while he is young you can make a rod for your own back. However, this seems to be the way out. Plenty of varied work to satisfy their thirst for activity.