A quote from Ray Bradbury:
If you are writing without zest, without gusto, without love, without fun, you are only half a writer. It means you are so busy keeping one eye on the commercial market, or one ear peeled for the avant-garde coterie, that you are not being yourself. You don’t even know yourself. For the first thing a writer should be is – excited. He should be a thing of fevers and enthusiasms. Without such vigor, he might as well be out picking peaches or digging ditches; God knows it’d be better for his health.
When was the last time you wrote something out of sheer fun or pure love?