It makes me cringe. I am never going to accept it. The choice to sleep without a topsheet when it is available is just… inconceivable.
When camping, it is fine not to use a sheet. But in a bed, night after night, putting your bare skin next to the blanket or comforter? Ick. Only if it is a duvet cover.
And yet, people do this! My own offspring, my flesh and blood does this. Why?!? Is it laziness? Does he really not notice? Is the sheet in the way of the blanket? Is the blanket too soft?!? Bedsheets have been around since the 15th C. Fitted bedsheets were invented in 1959 by Bertha Berman. A smart lady!
Oh, and even if we do use both top and bottom sheets, we should wash them every week to avoid skin reactions to the dust mites and their feces in our beds that feed off of our dead skin cells. Eeesh. And pillows should be washed every 6 months. I am off to do some laundry.