Like I said, it's not entirely true when you say, "I can't think of anything that is less about 'enjoyment of physical motion' than learning new park and pipe tricks." You're right that competition and ego boost are a component of doing tricks, but doing a trick successfully inherently feels good.
Well, in the full statement I made, I was saying that the pain (i.e. physical pain involved in falling and failing) of learning a new trick is far from physical enjoyment.
But I think the second part is about right and I'll agree. Too many different people out there with different views and motivations to paint as broadly as I did.