Each new quantum reality splits off when someone makes a decision. Every single world we've visited isn't just random - it's the result of countless choices, all of them combining to make a new reality.
If our destiny is nothing more than a prediction of a collision, an intersection between two paths, then we don't have a destiny at all.
I've been so shaken by finding my one worst self that I never considered how much it might change our fates by finding someone else's best self. Travel through enough dimensions and maybe you'll find the hero and the villain in everyone.