When I was growing up, I was always taught to do my chores, then I could play. But rather than simply enforcing the rule, I remember my dad actually explaining the logic to me while I was young -- basically, if you start to play first, the whole time you're having fun, you've got your responsibilities in the back of your mind (unless you're just a total slacker).

By getting the work done first, you actually enjoy playing more.

(Plus, if you play first then try to force yourself to work, it gets harder to switch context into a "work mode" and you end up not getting around to it a lot of the time)

I definitely notice that in my life now.