There is so much going on right in front of us, but we look back at what happened in a previous, nonexistent moment and parse, dice, and second-guess what could have or should have been said or done after the fact when it no longer matters. Do you see? That meeting with your boss, where you could have said this, other than that, the discussion with friends about world affairs and the point you were trying to make would have been better stated had you expressed it another way. That scarf you knitted would have been nicer had you thought of doing it another way, which you hadn’t thought of while doing it, the golf shot that would have been closer to the target had you only used this or that club, etc. “If only” is unreal, and to recount and rehearse what “might have been” will not improve anything you do now, including some learning you think will benefit you in the nonexistent future.
Living in the present does not give you a second chance to “get it right” in some well-rehearsed future moment. It just gives a brand new, fresh, clean moment, and whatever your performance is now is always perfect until you take it apart “after the fact.” Don’t take it apart! Smile at your dalliances with life and get engaged with what is right now. Life is not a performance-driven affair. It’s just fun if you let it be fun. You can’t fail, so let it go.