It seems nearly everyone has a phobia of some sort. Many are caused by events in childhood, even if it is something as simple as your father holding you up to see over the railing across the ocean.
I have only one real phobia: spiders (arachnophobia). I cannot stand the little things. I kill them without a second thought in my home and sometimes outside too. I am getting better about that part at least. If I see poisonous spiders near my home (black widows or brown recluses) they are dead.
I think it is because a brown recluse bit my father, you can still see the 2 inch diameter patch of dead skin on his foot.