Remember how in Superman Christopher Reeve spun Earth backwards to go back in time and save Lois? Turns out, he probably shouldn't have done that, because slowing the Earth's rotation to a stop would seriously mess with everything on our planet, as Earth Unplugged explains. Not cool, Superman.
And before you lecture me on comic-book physics and tell me Superman went back in time without reversing earth's spin: you're wrong. He clearly reverses direction to get the planet spinning properly again. [Earth Unplugged]