My first ever opening day of gun season, the one I had looked forward to going with my Dad for years, I fell asleep in the stand. I was in a climber with a shooting rail, laid my gun down across the rail, crossed my arms, laid my head down and fell asleep. When I woke up, I opened my eyes and was staring at a doe (I was 12 and I didn't care about big racks yet
)50 yards away. That was the only lesson I needed, and it hasn't happened again since.
Since then, I feel a little like I'm too observant in the stand in that I look too hard and move around too much. I'm sure I've been busted dozens of times without even knowing, but it's paid off plenty of times so I'm content.