Or, failure to enjoy when one feels that one is not enjoying enough. I guess there is a certain stress factor even in enjoying. Sometimes I feel that I'm not enjoying myself enough, and because of that I tend to enjoy whatever I do even less because I feel it's not worth my time and I should be doing something else. The solution is as obvious as it is impossible: find the right amount of enjoyment for yourself, so that it doesn't stress you out but nonetheless keeps you satisfied.
Forget about that, at least it's finally weekend! :D