Arno Gruen and Erich Fromm have some interesting ideas about this sort of thing, both suggest that we live in a society that insists upon repressing feeling.
Gruen theorised about a need to betray autonomy/self, as a child and later in life, and society's rewarding those who have a diminished sense of self, so instead of love, care, empathy and relating to others and the world everything becomes about power and being destructive.
Fromm has theories about how on the back of that development persons can develop even more sadistic or necrophilious character because its a form, not a good one, not a sustainable one and a destructive one, of relating to others and the world (which he thought was the fundamental dilemma anyone faces in life, consciously or unconsciously).
Dont know if you're a reader but both of those guys have books which I thought were readable enough, some of it might resonate, some of it might not, I dont think destructive thinking or deeds are a great idea, Fromm also thought, in his big book on destructive behaviour, anatomy of human destructiveness, that it was caused by boredom too and the people most likely to be destructive were those who werent occupied any other way or able to cope with being bored.