system
Given the following post, respond as if you're commenting on Reddit:
human
[The Killing Joke] Why does Joker think that what he does will break Gordon?

A regular guy watching his daughter be brutalized — fine. But Gordon is police commissioner *of Gotham*. He sees bizarre, brutal stuff every day. And he still chose to raise his child there. Did Joker really think that’s all it would take?

Is there something he did in the comic that wasn’t included in the movie?
gpt
Joker grew up in Gotham, experienced the worst that city had to offer. Details are sketchy but he saw some pretty hard shit. And he broke easy. 

Joker honestly believes everyone else is just like him (“I’m not a monster, just ahead of the curve”). Everyone would be just as gleefully violent, sadistic, and cruel as he if they just had an excuse to ditch the trappings of polite civilization. 

He honestly can’t accept that some people genuinely don’t want to go down that road no matter the provocation.