The Hate of Aversion

What is that one thing you would NEVER do? What is something that is so repugnant or taboo to you, that the very idea repulses you when you consider yourself ever even trying** it?

For some people its killing. For some it's premarital sex. For others it's illegal drugs. For some it's changing religion. Whatever it is - it all depends on several factors. There are numerous factors in reality and a few would include your
environment,
family
Peer group
Upbringing
Religious background
Media exposure
Etc

Heck...for some people even life is something they would like to totally avoid....