What I find very ironic is that Batman would never kill anyone, even if that person happens to be a major *sshole.
Capamerica told me once that Batman was on the verge of killing the Joker because of how angry he was, but the comic ends with the two of them laughing maniacally.
It would be weird seeing him rip someone's head off...
That actually wasn't the story. If he was referencing "The Killing Joke" the story was actually not about Batman about to kill Batman, but the realization that Batman and Joker on a set path for one of them to kill each other, either he would accidentally kill the Joker, or the Joker would finally succeed in killing Batman.
The story arc had Ms. Gordon (Bat Girl) getting shot and abused by Joker, and the Joker trying to push Commissioner Gordon insane...that the Joker believed it took just one bad day to make someone go insane.
The story was brilliant, and in the end, Gordon tells the Batman to bring him in by the books, that we have to show the Joker their way works. To honor that request Batman offers to personally work with the joker to rehabiliate him into society. In which case the Joker says he can't he has gone too far, and tells a joke that perfectly describes Batman and the Jokers relationship ending in laughter.
It is one of the finest Batman stories ever written...but Batman was not about to kill the Joker.