I had a small shop van. The ceiling height was EXACTLY 6'. I am 5' 10" barefooted. Add 3/4" for my work boot soles and you can see what is going to happen. One day, with an exuberance which I rarely displayed during working hours, I made a gleeful entrance from the ground into the van area. When I woke up, for the life of me I couldn't figure out why I was lying on my back looking at the ceiling of my shop van. One of those, "Good Lord, I hope NOBODY saw that" moments.

I have since made it a point to never display any excitement during working hours.