People often say “focus on what you can control” as if it’s that’s simple and isolating variables in life is as easy as it is on a problem sheet. There are so many things behind the phrase "let it go." History, attachment, hope, ego, fear, unprocessed conversations, futures that only existed in your head. Life isn’t a well posed problem. It’s chaos, entropy, with boundary conditions you didn’t choose. You can’t always cleanly separate the controllable from the uncontrollable when the thing you want sits right at that boundary. It is true that you can control the effort. But the gap between effort and outcome… that’s where frustration lives. And I wish I had something more reassuring to say about that.