we spend inordinate amounts of time looking at life's…
Keyword regret we spend inordinate amounts of time looking at life's rearview mirror. Most often because we're angry with someone or something they did to us or failed to do for us. Sometimes it's because we regret something we did or didn't do. The past can't be out undone. It's okay to glance backward but not stare.
— from Time
In the book
And here is the cruel trap waiting on the far side of waste — regret for wasted time is itself more wasted time. We spend inordinate stretches of our lives staring into the rearview mirror, replaying what is already behind us, burning present hours grieving past ones. And the third mistake is the quietest: letting other people spend your time for you. — Time
One: it was always your best mind that got you there. If you had had a better way to handle the moment, you would have used it — and knowing that lets you forgive yourself for what you cannot change. Two: you may glance backward, but you must not stare — obsessing about the past will never carry you forward. And when you have wronged someone, apologize cleanly: say "I am sorry for what I did," not the coward's "I am sorry for the way you feel". — The Heart in the Cockpit (Emotion/Awe/Anxiety/Regret/Empathy)