When I was a kid, it became clear to me that kids cannot win.
If I was watching telly, 'why are you watching that rubbish - there are loads of books in your room'.
If I was reading a book, 'why are you stuck in here with a book? It's lovely outside, get some fresh air'
If I was playing outside, 'why are you screaming and shouting in the garden - can't you make that racket at the park?'
If I was playing at the park, 'you've been at the park all day - haven't you got homework to do?'
If I was doing homework, 'you've been hunched over that essay all afternoon - why don't you come and watch telly with the rest of the family?'
For this reason, I was quite non-directive about how my kids spent their own time - and the result was that they sort of evened the whole thing out, over a while. So they'd go through periods of watching telly incessantly, and then they'd disappear off out for weeks.
Might just be my kids, I suppose. But I think a lot of parents are on the case daily - which you means you never find out what they'd do if you left them alone.