When you kept waking yourself up all night because you were snoring. dur.
I couldn't fall asleep and it took me forever to figure it out - every time I would be right at that relaxation cliff, I would snore. Not loudly, but my head would vibrate and I would wake up hard. This went on for next to ever. I finally figured it out and rolled over onto my side and then it was a very nice hour of sleep.
I hope that I can make it through my IATF 16949 update meeting this afternoon.