I've worked with some drummers that are off the wall nuts. But, also worked with some that are awesome drummers, and even better friends.
I think part of rock drummers are crazy thing is also part urban legend enhanced by spinal tap, Keith Moon, & Bonzo to name just a few.
Sid Bernstien's recent death had us talking about his outrageous offer to the Beatles around 74 when he offered them 120 million for a single show that would have been simulcast around the world. Paul and John actually gave reasons why they wouldn't do it. Some may remember SNL's Lorne Micheal's spoof of that offer when he offered the Beatles $3000 to do 3 songs on SNL. It almost happened when Harrison showed up on the set. And, coincidentally Paul was at the Dakota with Lennon,(last time they were together) they thought of taking a cab over to 30 rock to do it. George got the check. But the laugh was when Micheal's said. And I'm paraphrasing here. "Hey look I got NBC to up the offer to $3200, you can split it up 25% each or you can give the drummer less". I guess the point is drummers get no respect.