I think it is that the alternate paths are just so easy to romanticize.

I have been doing this lately with how maybe I should have went into the military after high school.

Of course, the romanticized version doesn't include losing a limb in Afghanistan.

It just easy to take the good fortune that did happen for granted.

Maybe an alternative perspective helps. If you could always do it over, an infinite redo so to say, nothing would matter. Every choice and outcome would become insignificant, because you could just redo it until it was just right. On the flip side, there's always going to be something that you miss out on, no matter how many times you could do it, some choices simply exclude other outcomes and you can't have both. The fact that you can't simply redo things is in a way what gives them value and meaning — what you choose matters.