Did I ever tell you the story (when I was growing up on the farm) about how we would just chop the heads off of chicken with an axe? That act does something to a person. I think I was 7 or 8 when I did if the first time. Worst part was finding the lower half of the chicken after the deed, as their legs still worked even if they didn't have a head.
Don't worry, I have since gotten treatment, and I won't kill again.