I accidentally left my slightly-more-than-professionally-testy “I am out of the office due to a lapse in government funding” voicemail greeting up for a couple months after funding was restored, oops.
I do typically come back to hundreds of emails, and I prioritize what to read – things from my boss/leadership are first, followed by communication from my direct reports. I also sort them by conversation thread and read the end of them first, which reduces the burden.

Naturally, she had to take the day off — and couldn't let folks know with any old generic auto-response. Instead, she made a guessing game of it in her out-of-office email, which you can use for yourself, below.
Given free rein, I’d absolutely love to tell people that needing me to show them how to do X in Excel is actually not a vacation-interrupting emergency and there are tons of free videos that would explain that, if they did not want to contact the actual departments who handle tech support and training. Or that this project they’ve known about for a month but decided to keep under their hat until it became an emergency is something they’ll need to resolve themselves. But that would not fly at all.