The interesting part of the process is developing the character, you know, why did he become that? Why is the guy a murderer, or why is this guy a pervert, or whatever he is. So that's the fun part for me to delve into the abyss. ↗
A lot of my characters in all of my books have a self-destructive urge. They'll do precisely the thing that they know is wrong, take a perverse delight in doing the wrong thing. ↗