If you're a lunatic in the DC universe, then you know all about Arkham Asylum. Ostensibly a place to cure the world's worst and craziest supervillains, it's never successfully accomplished anything other than giving Batman more work to do — here are the reasons why.
1) First of all, it's terrible at its job.
No one has ever been cured in Arkham Asylum. Well, not permanently, anyways. A few insane supervillains may have pretended to have gotten better, but most of them were lying, and immediately resumed their evil, murderous, insane ways the second they stepped off the Arkham grounds. The few who actually believed they were cured —much like Harvey Dent in The Dark Knight Returns — found themselves reverting back to their old shenanigans before too long, and taking hostages, robbing banks, etc. My favorite example is Cluemaster; Arkham actually did manage to cure him… of his pathological need to leave clues everywhere, but not his desire to rob and kill people. Great work there, guys. But the "not curing anybody" wouldn't actually be much of an issue except…
2) It also never holds anybody.
Seriously, anyone can escape Arkham Asylum. Actually, everyone has escaped Arkham Asylum at one point or another — the Joker, the Scarecrow, the Riddler… hell, even the Calendar Man has escaped on a few occasions, and his superpower is knowing when holidays happen. Many times the Joker has let himself be caught, because he knows with absolute certainty he can escape Arkham at his leisure. Hell, Batman has been forced to escape from Arkham himself a few times when someone's conspired to get him committed. Also, the fact that Batman and Robin an break into Arkham any time they want is also indicative of Arkham's massive security problems.
3) Some of the inmates aren't actually crazy.
Yes, the Joker is completely psychotic. Two-Face and Scarecrow are both pretty legitimately insane. And you could argue that the Riddler's mania for riddling is a major psychosis that needs psychiatric help. But Killer Croc is an Arkham "patient" and he's not crazy —he's just a thug with a terrible skin disease. Likewise, Mr. Freeze isn't crazy, unless loving your constantly on-the-brink-of-death wife is crazy — but he's locked up with the inmates of Arkham as well. If you somehow get tossed in Arkham Asylum and aren't crazy, there's a better than even chance you'll go crazy before you inevitably escape. Case in point: Warren "The Great White Shark" White. He was a Wall Street embezzler who pleaded insanity to stay out of real jail. He was tossed in Arkham and was not only driven insane, but was scarred by his fellow inmates until he resembled a shark.
4) The employees, however, are crazy.
Jeremiah Arkham, the chief psychologist and head administrator of the asylum, has gone completely bonkers on several occasions, even taking the identity of Black Mask during the pre-New 52 "Battle for the Cowl" event. He let the serial killer Zsasz make some architectural changes during a renovation, allowing him a secret series of tunnels through the building. The administrator after he was busted for his crimes was Dr. Alyce Sinner, who was Jeremiah/Black Mask's lover. Sometimes Dr. Jonathan Crane is presented as a former Arkham employee before turning into the Scarecrow. And everyone knows how the Joker turned Dr. Harleen Quinzel into his most devoted admirer and supervillain sidekick Harley Quinn, but he's also convinced many other doctors and staff members into doing everything from smuggling contraband for him to killing themselves. Which brings up another important point: The staff members who aren't crazy can almost always be bribed.
5) In fact, the staff was always crazy.
The original founder of Arkham Asylum was Amadeus Arkham, whose mother's suicide inspired him to devote his life to treating the insane. A nice thought, but it turns out Amadeus was repressing the memory of seeing a big-ass bat-creature tormenting his mother and slashed her throat with a razor blade to end her suffering. When his wife and daughter are murdered by the serial killer "Mad Dog" Hawkins, he puts on his mom's wedding dress and starts trying to do magic to imprison the bat-spirit. All he manages to do, however, is electrocute Hawkins under the guise of shock therapy and then get himself committed in his own asylum. And before all that, the asylum's original architect killed his employees with an axe, and also ended up a resident of his own building. This was NOT an auspicious start.
6) It's overcrowded and understaffed… and it's Batman's fault.
Besides the HQ, it can be argued that Batman is just as responsible for Arkham Asylum's problems as anybody. In recent Batman comics, we're introduced to an elderly inmate called the Anchoress, one of AA's earliest guests, who committed herself because she wanted an asylum to recover in. And then Batman shows up and starts dumping crazy murderous assholes in the building every other night, and the staff isn't even close to prepared to handle dozens and dozens of the world's most dangerous lunatics at the same time and the same place. No wonder they're not getting better! No wonder they can escape so easily! No wonder the employees go crazy themselves! In fact, in Grant Morrison's A Serious House on Serious Earth, Arkham administrator Dr. Henry Cavendish is so convinced Batman is the problem that he lets all the lunatics out in hopes that one of them will kill the Dark Knight.
7) Batman does not understand how mental recovery works.
Batman has his own HQ at Arkham Asylum. Now I know that doesn't seem that bad given that Batman needs to stop by AA a few times a week, to investigate a break-out, quell a riot, or threaten an incarcerated villain for information because they still have unfettered access to committing crimes on the outside. It just makes sense for him to store a mini-Batcave on the premises. But even if you don't buy the theory that Batman creates and/or enables his rogues gallery by his very existence, how much could it possibly help the patients there to see their worst foe stroll through the hall every Tuesday night? I think that might make their recovery a touch problematic, don't you? Even more terrifying: Once, Batman had to take a trip somewhere, and Ra' Al Ghul was in town and Batman wanted to get him out of the way. So he plants a bunch of fake medical records, knocks Ra's unconscious and drops him off at Arkham telling the staff that he's a criminal with multiple personality disorder called Terry Gene Kase, who happens to think he's Ra's Al Ghul at the moment. Batman had Ra's committed just to keep him busy. That's so fucked up.