Pragito Dove, in Lunchtime Enlightenment Chapter 2 ("The Laughing Buddha: Enjoying Your Way to Enlightenment") observes:

Meditation isn't something you have to work at with a straight face. Be sincere about meditation, yes! but not serious, because then you will try to force and achieve. This will only create more tension. The more fun you have with the various techniques—the more playful you are as you approach them—the more relaxed you will be and the more you will want to keep meditating.

^z - 2010-11-08