[fouric]

> If you are too busy, you will not think of the optimal solution to your intellectual problem.

Yeah, lots of people have noticed that when their brain is not busy (taking walks, taking showers (/r/showerthoughts), in a hammock), they frequently come up with creative solutions to their problems - and at least one kind of leisure that GP mentioned (gaming) generally pretty strongly occupies your mind and prevents this exact kind of (uh, "diffuse"?) subconscious thinking.