If you get annoyed by people using their vacation time you should rethink staff levels so a single person taking a random day off doesn't impact operations. They've earned their vacation and they should be able to use it as they please. Granted, I don't manage non-exempt service level positions, but the employer should always encourage vacation time. It's good for moral and a happy employee is a good employee.
I'd take off to play with my new tractor.