"I’ve been looking for my glasses, presumed them lost, found a spare pair, put them on, only to discover that I was already wearing the first pair.

"
You are not alone ...
On a slightly different tack, I've recently spent a week in hospital. Been on drips of one sort or another virtually all the time. They encouraged me to drink lots of water, at least two litres per day which of course means lots of pees, day and night, and when you go, you need to take the drip stand with you.
First night home, got up in the early hours for a pee, must have spent five minutes groping around in the dark trying to find that stand until the penny dropped and I remembered that I was at home and no longer on a drip.
Still did it another two or three times though!
Frank