Now that I'm doing some part-time copyediting, there are a few things I have to obsess over. Like "OK" vs. "Okay." My rough intuition is to use both in different situations: "I'm OK, it was just a bruised kidney," but also, "Okay, let's get this borscht-eating contest over with." I could also see how some writers would be more suited to "OK" and others to "Okay"--they give off different atmospherics. But I can't really put my finger on it.

For that matter, I have yet to resolve "borscht" vs. "borsch." Neither has the clear edge on Google, although the extra "t" really is a nice touch.