When I don't accomplish anything.  Doesn't have to be anything grand but I have to 'do' something toward the mental checklist in my mind or I go crazy.  May be as simple as finishing a book (or chapter) up through huge work projects.  Even when I'm sick (I've never been so sick or injured as to be unable to function, praise the Lord), I have to get out of bed, take a shower, etc or I feel like a total slacker.

'And those seen dancing were thought to be insane by those who could not hear the musicNietzsche