In my experience even the best traders miss opportunities. Mastering the negative emotions makes it possible to survive and navigate the seas of the market. If you only focus on chances missed, or value lost, you will be driven by fear and greed. These are both not very good advisors, and I think they do not bring happiness.
A large part of mastering trade is mastering yourself.
Just my two cents. Hope it helps.
For me this is what makes trading fun! It's exciting and less boring if there is a risk that your investment loses. Say for example all your investments profit, it would be boring and predictable (at least for me). This is what makes you appreciate your winnings. How i handle losing? I move on