I knew of some former Pony Clubbers, now moms, who had a little program going for foals at a TB farm in Kentucky. Those ladies were awesome.
They took the foals on walks, braided what they could on manes and tails, groomed endlessly, basically played with them, around cones, over bridges, through mazes. They always had snacks and music in the barn.
Those foals had the best manners and were lively and engaged, and the moms got horse time while family duties kept them from being horse owners.
But, me? I'm more like Foxhunter. Once halter broke and able to be handled, I leave them be. And mine are well mannered, too.