I think it's like washing dishes. Kids love dashing dishes becuaes they think they are playingin the water. They'll wash dishes all day long. But once puberty happens a light bulb goes off and they realize that washing dishes in now work. Therefore, they hate it.

However, I agree that cycling is the most fun part of my day but the reason I don't as much as I can is because riding for me is painful. That's why I getting a bent to make things more comfortable!