Don_DickleHas there ever been a reason why the Joker turned or was always evil? If one bad day did it wouldn't he first fall into a depression of sorts? And has joker ever been shown being with a woman?
As a comic book character Joker and his origin has many variations. The most common is that he was already a depressed low-level criminal (red hood). He gets chased by batman and falls into a chemical vat that results in the white appearance and green hair. The further societal exclusion makes him blame Batman and society which then becomes a feedback loop.
Joker has had strong implications with Harley Quinn (she was never solo in early work) and some others.