Granted. You and Emmett Brown fly back to the future in a search for something erotic. You bring back an almanac of eroticism, which promptly falls into the wrong hands and completely corrupts the entirety of our modern society. The future is inexorably changed. Erotic and kinky become the norm; thus, that almanac is never published since such things are commonplace in every day life. Since the almanac is never published, your trip to the future is in turn negated, as are the effects of the trip and the resulting arrival of the almanac in your time. The entire trip was a waste, and you're still no closer to bringing your search to fruition.
I wish I had a dictionary built into my brain.
EDIT- Ah hell, Maeven beat me to it.
Granted, but you become extremely ill whenever you set foot on land; consequently, you are doomed to a lonely life at sea, smelling just like the fish that surround you. Water, water everywhere, but not a drop to drink...or wash that fishy smell between your thighs away with.
Again, I wish I had a dictionary built into my brain.