With all I've seen, it's the behaviour of some people I find disgusting.
Madness string 96976
My Dad tried insisting he was a spirit when I'd ask as a kid, so that did screw me up for awhile because I was scared that people I loved were spirits and would 'cross over' and leave me, and no one else would remember them.
Man's natural state is slavery; we are unhappy because we are too 'free'.