“Many people reveal details about their personal lives in an OOO — like where and when they’re traveling,” Tim Sadler, CEO of Tessian, explains in an email interview. “Whether done on social media or in an auto-reply message on email, this arms hackers with the information they need to either craft a convincing email targeted at the OOO employee or impersonate the person who is on vacation and target one of their colleagues.”
I actually think that’s a really helpful out of office message? I appreciate how clear it is about who to contact in which circumstance (so you’re not having to do the awkward dance of trying to track down the right people while not inconveniencing the wrong ones), while maintaining a friendly-but-firm boundary around the vacationing person’s time (since none of the options include things like “here’s my cell phone number!”).

In 2013, researcher danah boyd wrote a LinkedIn blog post advocating for the nuclear option which was framed in the piece as an “email sabbatical.” Coming back to an empty inbox after a vacation is should be a break from the insanity, not a procrastination of it,” boyd wrote of the decision to send everything to the trash.
Start with a friendly greeting. Skip the "Greetings," "Salutations," "Dear sir/madam." These are far too stuffy and robotic. Instead, start off your response with a simple "Hi" or Hello.