Possibilities are infinities that exists amongst infinities.
Assuming that you can predict that each individual decision you make represents one out of the infinite possibilities, to which your follow-up action has a comparable number of options, an algorithmic analysis of all possibilities would entail the following statements:
(a) The number of possible combinations exceeds the known universe
(b) Paralleling cardinality of the continuum a la George Cantor's 1874 uncountability proof, there exists different infinities. (Cross-reference to John Green's "some infinities are bigger than others")
Keeping this is mind, what would you have done differently in your life? Or what would have changed if this happened instead or that?
Of course, my line of thought should rationally end here as this is a thought experiment and, according to my professor, "thought experiments are rendered moot because it's not feasible so why bother", but I simply couldn't help myself.
There is always this fantasy about a parallel life - she would get immigration papers, he would come home safe from the war, we would get married and have a beautiful house in the country with 2 children and a dog etc. I do this all the time. I construct my own version of the perfect parallel universe; in another life we would have talked, you wouldn't have gone away, I should have showed you how much I cared, we would have exhaustedly held each other under the sheets, knew that this was too far gone, there would be a future after this is done.
But these are dreams that hold as much weight as emptiness. This is not a perfect world. In its place, almost every night, I am wrecked with nightmares about the what-ifs and the could-have-beens and when I wake up, my heart aches so badly and it dies a little.
It is my greatest wonder if the I, who lives in a parallel universe, is happier then the I who exists here.