I mention in Screw Work Let's Play the theory that there are parallel universes. The theory suggests that for every choice you make, there is another universe where the opposite choice plays out.
Now, I use this idea simply as a thought experiment to allow you to think what it would be like to be able to play out every possible choice about your work. But some physicists take this very seriously as you can see from the BBC Horizon clip below.
As one scientist puts it, "Anything that can happen does happen". That means that there is a universe somewhere where John McCain won the last US election, one where Elvis Presley is still alive, and another one where you were never born.
The interesting question for me is to think that for all those choices you made in your life, the opposite choices are playing out somewhere. If you could jump to one of those parallel universes, which would it be? And since we don't yet have a way to make that jump, how can you take your life in this universe one step closer to the one you prefer?