Sorry for the threadomancy, but I wanted to update about my cranky co-worker.
I seem to have discovered the trick in dealing with her. See, the thing is, she gets particularly scratchy about being told she's made a mistake, so whenever I find one and have to take it to her to fix (I've found several since I've been back from holidays but I can't be too hard on her after finding out her mother passed away over the holidays; not surprising she's a bit distracted) the key seems to be, instead of saying "I found a mistake" I should say "I have a question". That way I'm not accusing her (or anyone) of having erred, just that it's me and I'm looking for clarification.
Yesterday I was checking over an order my coworker Romeo was about to pack and send out. I checked over the paperwork and noticed the serial number listed as 214**. I thought that was weird, as we're currently in serial numbers starting with 24, so 24***. Sharon was right there so I said, "Sharon, is this supposed to be 241**, or did we just need to use up an old serial number?" FTR, using old serial numbers does happen, but rarely. Sometimes it's a long stretch of time before we sell one single unit, rather than several at once, so sometimes we get lonely singleton serial numbers that remain unused for awhile. It's totally not unheard of, but to go back as far as 21*** when we're currently in 24*** is pretty unlikely.
Sharon just laughed and said, "Yeah, looks like I had a dyslexic moment. I'll go take care of it." She took the paperwork and brought it back corrected right away, no huffing, eye-rolling, or snark. I've been sticking to my phrasing of "I have a question" rather than "there's a mistake" and she's been all around more pleasant to deal with, for me at least.