Usually get like that when I regret doing the session. For me it's when my expectations were too high going into a 300 - 400/hr session and it ends up being a "meh" experience. Could of did a BNG and kept the change..
I recently saw a lady who advertised that she was the most passionate kisser here and I love kissing. I went and she was the worse kisser I ever met. I was like WTF was that. An extreme waste of time and money