I had a free upgrade to first class for 1 hour on a flight SYD-BKK once.

My friend invited me to keep his seat warm while he was sampling the scotch and chatting up the FA.
I was asked to leave after about 1 hour as the other first class passengers complained that I was too excited and they were trying to sleep.
I thought the whole idea of flying first class was for the added pleasure. Why spend all that money or points on first class seat only to fall asleep. :?