Thanks for the question. After thinking about it, I realize my intent wasn't as concrete as I thought it was. I think I consider worthwhile problems (probably a better word, and truer to what I intended) to be ones that have rewards outside of pure entertainment. For example, spending time on Candy Crush or Pacman doesn't seem to help anyone with anything other than those two games. Now one could argue that games like Factorio and Kerbal Space Program are more rewarding, and I would agree to an extent, but much of the time they are still solving toy problems. If one must use an abstraction of a problem to approach the realm of the problem due to limiting constraints, like not having access to a hangar of rockets, I am more understanding.