Change one small part of a plot line to completely ruin a movie?

Heres a couple to start with;
Back to the Future - The Libyan’s gun doesn’t jam when he’s in front of Marty

Shawshank Redemption - Andy Dufresne’s cell is not on an internal boundary wall

Cars - Lightning McQueen didn’t mess up the road in Radiator Springs and just carried on with his journey