Ha, sounds like my day yesterday. We decided on very short notice to submit a proposal (has to be in today).
Spent five and a half hours writing it (there were serious constraints), only for the boss to turn up 10 minutes before closing, and decide we'd missed the point of the proposal.
After 10 minutes of arguing, I told them I'd spent too long on it to be able to be objective anymore, and went home.
Waiting to see what they decided in my absence.
--A