When I turned 45 (10 years ago) I met an old guy who had been a WWII vet. He'd been a fighter pilot during the war, and even though he had snow-white hair he was still a pretty formidable guy. He was talking to me about a much younger guy, a friend of his son's who'd ripped him off for a few thousand dollars and the old guy said he was gonna go see him and was gonna beat him so bad the guy was, "gonna pi$$ blood for a month!".
I laughed, but I bet the guy who ripped him off didn't. Then he asked how old I was, and I told him 45, and he got this real wistsful look in his eyes and said, "Damm... I wish I was in my 40's again!" It puts it in perspective.
I think he flew P-47 Thunderbolts.