At first it was amusing as I started to make more blunders -- one day I made five mistakes before breakfast! But it's turning into an embarassing part of getting old.
My grandfather was a bricklayer, and a hundred years ago I'd have admitted I was becoming one brick short of a load. Then when I was a kid and boys spent quite a bit of time stooping over circles traced in the dirt, it would have been doesn't have all her marbles. (What ever happened to marbles? I'll bet my grandsons don't even know how to play marbles.)
Recently it's likely to be elevator doesn't run to the top floor, dullest knife in the drawer or light on but nobody's home. And now I understand the most up-to-date description of this condition is
one fry short of a Happy Meal.