Without being able to view parallel threads of existence, how can we know that going by the road not taken has made all the difference?  We don’t even remember the road we did take with accuracy.  One missed opportunity might not have been an opportunity at all, and viewed backwards through the lens of envy and regret, the image twists into something unrecognizable from the original imagined goal.  Lost love or a dodged bullet?  Great riches and acclaim or blindness to the world. One piece of information, at the right time, to a receptive mind can turn everything that was held to be immutable into quicksand; or wings.