I've an uncle who wore a mustache for pretty much all my life. It wasn't a little skinny thing like my dad's (who apparently was told at one time he looked a little like Clark Gable, hence the skinny 'stache), but not a huge handlebar like Geraldo's. Somewhere in the middle, full, but well trimmed and neat.
A number of years back, my mom had had some surgery. That half of the family is the Italian side; when someone is in the hospital, for any reason, it's mandatory for all the extended family to show up and
When I walked into the room, my sister, her family and this particular aunt and uncle were already there. I said hello to everyone, then turned to my uncle to ask, "When did you shave off your mustache?"
The entire room erupted in laughter.
It seems he had shaved it off several weeks earlier, on a whim one morning. When he came out of the bathroom, my aunt didn't say anything about it. He decided to wait to see when she, his wife of fifty plus years, would notice that the soup strainer was gone.
It took the better part of the week, and in the end, he finally had to tell her. There was nothing wrong with her eyesight...she had just had a lot of other things on her mind.
We see what we expect to see, I guess. One thing I'm sure of, though - my aunt started regularly checking to see if my uncle was regrowing the mustache. She wasn't going to be caught unawares again.