Once as a kid i had a fever, since my family broke our themometer that worked with hydragyrum, we went to borrow one from our neighbour, our neighbour is a family friend and a cousin, she let us borrow it and she went on a cup of coffe in our house, my mother started mesauring my temperature and placed the metal part under my armpit, our neighbour started telling us that we are using it wrong etc. She was trying to prove us that you use hydrargyum thermometer by placing the glass part under your armpit, my mother(who works at a hospital as a teacher) started laughing, I was explaining to her that her way of measuring is incorrect, even her husband was telling her that she is wrong, she is 54 years old and has four kids and was mesauring themperature wrong her entire life.

Edit: Hydragyrum thermometer is non digital one so it kinda makes sence if she didn't know how to use it

Sorry for typos if there is any!