My grandparent’s faucet in their upstairs bathroom is one example of what Don Norman was talking about the historical problems with the design’s of faucets.
This faucet has inability to change the flow of water. You must pull the knob outward all the way out in order to get any water flow. Since the handle is a knob, many first time users can have issues in knowing to pull it outward and only know to turn it left or right. Every time that I use this faucet I get confused which direction that I turn to get warm water. Even with the colors are on the knobs, it is very confusing because the knob can be sometimes turned upside down. This causes the colors to be flipped flopped and the red color on the right and me to turn it right for warm.
If only like Norman said, designers could agree on a standards when designing faucets. Standards seem like the number one solution to make it easier for users. There are so many different designs of faucets that users need to recognize or force them to struggle in how each type of faucet functions.