I look at it like taking a walk, or a smoker taking a smoke break. That small reprieve, the 15 minutes I take working on a side project, or tinkering with something for fun, rejuvenates me and gets me jazzed about the task at hand when I get back to it. That's a productivity booster, and ultimately a benefit.
A rationalization that's likely to get you fired if you were to own up to it publicly. Although it's true, the company would benefit from you feeling excited about the task at hand.
