The best retroactive genius moments are when I invent or discover something that has been around my entire life – something “hiding” in plain sight. I like to think of it as inventing the obvious, or a “DUH-scovery.”

At 55, I realize that there’s no way I am going to look years younger. Looking years younger takes lots of time – and lots of money. Those brown spots on my face from the decades prior to sunscreen aren’t going away with fade creams. Fine, I’ll have a doctor laser them off. The sticker shock sends me running for the concealer. I have half the hair I...