Response you give to your friends when they ask you why you are behaving in such a ridiculous manner, and you really have no reason for it other than -just because you can-. Generally accompanied by a shrug of the shoulders
An attempt to justify your stupid actions
Derived from the Applejacks commercial a few years ago:
"Why do you kids like applejacks when they dont taste like apples???"
"We just do!"
Fred: Why in the HELL have you been walking in cirlces for the past 10 minutes?
Joe: I dunno, applejacks.