Whether the cause is months of mounting pressure, a Sisyphean inbox or the insult of meetings insistently scheduled before 10 a.m., there’s nothing more tantalizing than the thought of escaping work for a week, in my case to a cottage with no Wi-Fi.

Cue the out-of-office email. In theory, its premise is to let colleagues and correspondents know when you’ll be back and who to contact with urgent queries in the meantime. In practice, however, the etiquette surrounding out-of-office responses varies—often to quite wild and, worse, wacky extremes. It is telling that some employers require a simple “I’ll reply in a week,” while others seemingly expect the precise geolocation of where you can be found if clients can’t wait until tomorrow.

There are national cultures surrounding ...