But your out-of-office message is as much for you as it is for the people receiving it, especially during the pandemic. “Boundaries have taken a big hit right now,” Ritter says. There’s a lot of pressure associated with missing something at work, and that stress has been heightened without the typical separation between office and home and with the added fear caused by an uncertain economy. An OOO message is a chance to set expectations, “to give yourself some breathing room and to ensure other people aren’t thinking negatively about you,” Ritter says, and it’s crucial for your mental health.
I find it rude, as well. If someone is emailing you (the royal you), it’s because they need something. Saying you’re just going to delete it without also giving that person a Plan B contact is totally rude. It sucks having to go through emails, it does. But it’s part of the job. In my role, I get requests from internal colleagues and from external partners. Even though I provide those partners with an alternate email to send their requests, it’s still my responsibility to make sure that the requests that were sent to me in my absence were handled. Saying “everything I’m sent will be deleted” just Would Not Fly in my industry.

“Depending on your company culture or your potential audience, you can craft a professional message or take a funny, creative approach,” according to Indeed.com.
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.