your memory.
.
My memory is weird. I can remember details of matches in the early 90s and the day trips around them enough to write about them, yet often I find myself saying things like "I need to use that THING.......you know, the white thing you do a poo on......the thing in the bathroom".
When you get to our age I have a theory that the brain is fairly much full up and stuffing something new in makes the word for spaghetti, or dog, or aeroplane fall out.