I think it's a pretty fundamental problem, and a difficult one.
Something like eating is fun while you do it, but you don't remember it all that well. Something like exercise might be a pain while you are doing it, but when you think back about it you are happy you did it. And it brings rewards.
So we have the idea of "worthwhile" things vs temporary pleasures. But I don't think that gets us very far. We aren't good at predicting what will make us happy, so pursuing "worthwhile" things can backfire if we choose wrong. And how much of your day do you spend remembering things? You may go on a two week vacation and only spend an hour remembering the rest of your life.
I don't think the question is answered by looking at various activities or things you can do. Your attitude is the key. With the right attitude, worthwhile things become associated with happiness, and you enjoy doing them. And that kills both birds.
Using your willpower to make yourself do worthwhile things instead of just enjoying yourself is a dead end street in my opinion. Exercising self control requires energy. We don't really have the perception of the brain using energy like we do for our legs (we know they get tired after running), but it does. The more you have to exercise self control, the less energy you have remaining for other mental activities. And why would you want to have to force yourself to do things anyway?