To have your plans foiled by an inadvertent action you made.
As you attempt to make thousands of dollars by betting on a football game you know the outcome of, the squirrel, that you puked on, after just waking up from a drunken haze, in a hot tub, after travelling back in time, appears on the football field, and changes the outcome of the game.
Dude: "We didn't travel back in time so you could bet on football"
Bro: "But I know who wins"
Dude: "Go for it then!"
Dude: "How much did we make??"
Bro: "Nothing, I ended up squirrelling it"