So many great replies in this thread! My view is that they never think about other people long enough to "set out to destroy" anyone. My ex was so self absorbed I don't think she thought for a second about anyone else, everything about their thinking is me, me, me. Their condition consumes them.
I do agree, it is all me me me for them... .but that said, I disagree that all aren't set out to destroy anyone. Obviously everyone is different. And my ex certainly didn't set out to destroy me... .but after enough recycles and enough delusions about me having affairs with other coworkers, he made it his mission on more than one occasion to destroy my life and teach me a lesson. His words. Destroy my life and teach me a lesson. And when he snapped out of his psychotic state or whatever it was - he was SO upset that he did anything that could affect my life and that of my child, he was SO apologetic. For one day. But now... . he's burying those very recent memories and yet again painted me black.
Maybe it just depends on what state of mind he's in... . I really don't know... . but I do know the right circumstances with the right trigger, no matter how completely innocent, can spark very intense reactions... .