A "Norman Door" is a door whose design makes it hard to use. It can make you feel foolish, but it's not your fault! It's the design. If a door needs a sign for you to know how to operate it... something went wrong. Named for designer Don Norman, such doors are a great example of why design is so important!
From a Gary Larson cartoon.
Listen to this 99 Percent Invisible podcast
Take a class with Dr. Record! LB 322A/B Advances in Science and Technology is an especially good bet.
Here is a door sign I sometimes use. The QR code leads to this page. Feel free to use for your own educational purposes!