I've been researching forties things lately (surprisingly, not for an Avengers fanfic), including cocktails and slang and charming expressions of yesteryear. I was looking for a suitably antique-but-urbane "He's crazier than a ______" and stumbled onto a list of random country expressions. My favourite, I think, is "He'd gripe with a ham under each arm." (partly because it reminded me of Neal Caffrey, Pig Thief.)

I didn't end up finding a cosmopolitan "crazier-than-a" so I ended up giving the line to someone else, which I think actually works well:

Bruce Wayne: "It's not like he can go out in the daytime."
Clark Kent: "Plus he's crazier than a sack of snakes."
Bruce Wayne: "That too, and what a charming colloquialism. Smallville in origin?"

Not only is it not Avengers, but despite the above exchange it's not even Batman/Superman. It was supposed to be about five thousand words to entertain a friend, and it's now at thirty thousand and rising. There are secret agents and robots and swanky nightclubs. And no sex.

Story of my life.