Death and other icky stuff

A friend of mine stopped by my desk the other day with some news. His ex step-daughter was just found dead at 24. She leaves behind a mother, a brother, a boyfriend, and a daughter. It was a shock in some ways to everyone. But in others, I have to say, it should've been expected. I intended this to be a rant... and maybe I'll come back and rant about it later. But right now, all I can think is, why? why do people do things that they know hurt the people they love?