That said, be careful with messages that are this curt. Make sure you're familiar enough with your audience — and your boss, for that matter — to know that this sort of out-of-office message will be met with a snicker, and not with annoyance.
Agreed! A bit of warmth is fine, sure, but it’s not the place for chattiness — that’s for talking to an actual person. I want an OOO message to tell me that the person is out, when they’ll be back, and who I should contact in the meantime if need be. No objections to multiple options there, whether it’s “X for llama grooming issues and Y for llama tea parties” or “X for routine questions, Y if it’s urgent, Z if it’s an emergency,” but I want to be able to absorb the useful info quickly and move on.

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My OOO is almost always “I’m out of the office and will be returning on x date.” My email sig has instructions along the lines of “for questions on x, email this list” for a couple of the more common areas people would contact me about that might need an urgent reply (as the lists go to more than just me, obviously), but most people have finally figured out to contact those lists to start with, anyway. If I were in the middle of a project or something that needed to be moved along in my absence, the project teams usually know when we’re out, but I’d put a back up in that case, if needed, but generally there’s not much to be gained by a longer OOO from me.