"something they absolutely hate" is learning to read sheet music, training for skill, practicing for muscle memory.

The fruits are reaped when they (me!) get older. Like I mentioned in another comment, I can play along to a song I like, play a song that is a certain memory, jam with friends at a whim.

Those are not things I necessarily wanted to do when I was a kid. But the "forced" practice was required as a foundation to do what I want to today.