Wow... did we just have a reasonable discussion on slashdot? That's creepy. :)
But yeah, modifying production code on the fly was something that took me a while to get used to. I had come from a tradition "IT Environment" in which you had programmers coding in a dev environment, and test environments, and staging, and deployment... etc... And suddenly, I find myself in an environment where you *can't* really have a test environment. How do you test, for example, a mile long conveyor that diverts packages at 100 feet per second accross 250 diverts. Particularly when one of the primary things that goes wrong is that the electricians wire up motors backwards 1/2 the time :)
So yeah, it's been a bizarre transition, but even though I now have to routinely be *at work* by 5 a.m., I love ever second of it.
To be completely honest, I wish I could program (and have my staff program) in Common LISP or some similar language, but the fact of the matter it's that it's hard enough to find dependable programmers, much less dependable programmers willing to be at work at 5 a.m.... and even less dependable programmers willing to be up at 5 a.m. and hack functional paradigm :)