To cheat on your wife.
"No but I heard he's with his girlfriend behind the bleachers. They're hiking the Appalachian Trail"**winks**
"Oh that dirty bastard."
Boss asking for a note on why you were out for a four-hour lunch with his wife? Yep, you guess it - you were out hiking the Appalachian Trail!
See also Sanford, soon-to-be-former Governor of SC.
A: I hope he's wearing a condom.