Here's an example of a head shot gone bad:

About 15 years ago on the third day of PA's bow season, I had just gotten in my tree when I saw a deer coming. I quickly saw the antlers and decided that it was a shooter. As it approached me itwas grunting loudly with every step. Then I noticed its tongue hanging out and it's mouth was open like it had been running hard. I thought "this is a bit early for rut behavior". he eventually passed almost under my stand and I shot him through both lungs at about 6 yards quartering away. When I picked up his head to admire the rack, I noticeda cut on the top of his nose. Furher investigation showed that some jacka$$ had shotat his head straight down. The broadhead was lodged under his chin and the shaft was broken off with about 6" of it stuck in him down through his mouth from the top. His tongue had been hanging out becauseit was about 90% severed. he wasnt grunting in rut, he was grunting in pain! That buck would not have survived and would have died a terrible lingering death if he hadn't happened by my tree.What a shame it would have been for a nice racked mature deer to take days or maybe weeks to die and rot because some fool took an irresponsible shot!