To avoid inbox shock when returning from vacation, a lot of us check email constantly while on vacation. It's a pretty awful way to live if you think about it.
Around the 10:30 mark of his TEDxNashville talk, "My Digital Stamp," Erik Qualman solves this problem:
When your vacation starts, set your email's vacation auto-responder to say:
Thank you for your email. This mailbox is temporarily full. If your email is important please resend it on [Return Date].
When you return, select all the emails you received while on vacation.