It's 1922. Your great-grandfather, a time-traveling handyman, has just fixed the loose hinge on your great-grandmother's time-traveling watch. But now, every time you look at your great-grandfather's photo, you're reminded of his meddling.
Hyper-link to the TimeParadoxes wiki:
Learn more about the Butterfly Effect Bungle Explore the Predestination PredicamentOr, if you're feeling particularly reckless:
Get a time-traveling tattoo of your great-grandfather's face with the loose hinge