Opportunity cost is insanely wicked. There is so much, "i could done this", "i would be rich now…" "if only i had done…"

If you are good at analyzing trends so you can use that information in the future to calculate EVs, then you should go over them once. And only ONCE. Else, you are wasting your time, your now, crying over spilt milk.

The weird thing, speaking from a law-of-attraction perspective is that all of your choices would have led to about the same outcome. If you believe you will get a 10% return, and you commonly get 10% return, then you will get 10% return. If you believe you will get a 10% return, and you commonly get -5% hits, and you haven't done anything to clear this energy patter, you will most likely get -5%.

And the decision would not have made a difference.
Choosing pineApple or Goolag, which ever you chose, would be the worse performing stock.
But we cannot really prove that, because we don't have a time machine where we can not bias ourselves to the results previous.

But, damn, calculating opportunity costs beforehand can be a pain in the ass.