Given a choice between two theories, take the one which is funnier.

This is commonly known as Blore's razor, though I haven't met anyone who knows who Blore is, or if he or she even exists or the name was chosen for sounding funny. While at the first glance it seems like nothing more than a parody of Occam's Razor, it is in fact also a fine guideline to making your life a little more interesting.