About 10 years ago I nearly knocked myself out cold on a golf course....
I was about 15 feet behind a tree that was only about a foot wide at the base and where the lowest branch was about 8-10 feet above the ground. So I figure I can use my "tree iron" which is an old 1 iron, I could easily keep the ball lower than the branches and get the ball safely into the fairway, WRONG, the ball hits the tree about 3 feet up and ricochet's straight back and hits me square on the chin before I even finished my swing. My knees buckled and I dropped to the ground and just sat there for a few before getting back up.