I’m not taking about not being allowed to feel happy. People who have a neutral facial expression aren’t all depressed and unhappy. Just like people who have a constant smile on their face are not all happy. For many Americans it’s the norm to constantly smile even when you are unhappy like when you greet people even when you just walk past some stranger on the streets. While in many places in Europe that would be seen as creepy where the neutral facial expression is normal. Like if you go into a store in the US especially one of a big corporate chain you get greeted by an employee with a fake big smile on their face. Which is not the norm in many places in Europe.