Words that are used only in the plural

I was in the Army with a sergeant above me in rank that always put an S on things that were meant to be singular, like saying Feets that drove me crazy when he said it. He could not say hand or hands either it was always Handsts, or Hats when asking a person where is your hat he would say where is your hats! It drove me crazy, but he out ranked me so I just smiled.

So, I understand.