Answer:
This question can technically not be correctly answered. This question is an opinion question. But in my opinion:
Many people say the joker is indeed insane or deranged. Yet in my opinion I would strongly disagree! Though the joker can act crazy to the extremes, he simply just thinks differently, just is misunderstood. So apparently he thinks "weird" according to you people but he's just as "weird" as you!
-Jokerfan07
Ever since Grant Morrison wrote "Arkham Asylum:A Serious House on Serious Earth," about half the comic community took to heart that the Joker is a supersane sociopathic actor instead of a genuinely insane psychopath. It really depends on the writer. Much like the way an actor changes his personality from movie to movie, the Joker will tire of his ways & reinvent himself every so many decades. The original Bruce Wayne Batman & Red Hood (Jason Todd), & possibly the new Batman (Dick Greyson) believe the Joker is sane enough. Yet a few times the Joker has stated that the world is a dream & only he & Batman are real. It's also possible to be half-sane; where you have various mental disorders but aren;t genuinely crazy enough to be institutionalized. Look at the Joker's love life; is he asexual, bisexual, or gay? Outside of Elseworld's comics, he's written as celebate, but he's a sadomasochist who loves the feal of pain. He provokes big men to fight him & he beats on women. Violence is his sex life.