No doubt, but it's a problem I'm willing to struggle with :)
I think it's part of the worry people have had for ages and ages: what do you do idle? Do you find things to do? Or just stop doing things? Or do you create and/or learn a skill? Do you work harder to leverage it all for power?
Well, do you have hobbies? Interests? Things that you think about wanted to do when you're at work? Things you have to stop doing because gosh darnit you need to get up for work tomorrow even though you'd rather carry on until morning? If you have those, then why not do them more?
All those things you enjoy and do without question or thought, or wanted to try, those are the things that you do.
Yup. I suspect I (with likely a large number of people who tend to sites like this) would have no problem filling our time well. And for those that don't, I'd bet a good number of them could learn to :)