system
A chat on subreddit /r/me_irl
human
This is true. Also believe or not violent crime as a whole has been declining over the decades. Especially murders seeing it's really  hard to get away with it with forensic science now. A good example is the guy they just got for all those murders in I think Idaho.
gpt
Lead poisoning is becoming less common because we took it out of almost everything. It literally made everyone violent idiots.