WM, at least you didn't get home and start searching for the key which was in your hand and then go back to the garage, after putting it back in your pocket, only to find it in your pocket later...
That's the kind of thing I do.
Cruiser, I now have 3 full sets of screwdrivers, sundry other tool duplicates and multiple tape measures because of this invisibility issue. It seems that my mind, once it has decided a space is empty, won't see anything in it until I get a fresh perspective.
I also have an issue with knowing where something is (pocket for instance), looking for it and not finding it for days, only for it to turn up exactly where I was looking for it in the first place....
My "Plonker" moments are getting worse as I get older.
But I do rarely forget to tie up my shoelaces.
Although that may not be too much of an indication because I tend to buy slip-on's nowadays...
There is, however, the possibility that I might forget to put my shoe on...