People who always act happy even when they're not

I hate fake happy ppl

It can be. I don't think there's ever just one overarching answer when it comes to human behaviour. One persons trauma response can be another person's copying mechanism. Everyone's baseline is different.

Usually, the happiest acting folks are the saddest and they use it to mask their sadness and depression and sadness.

Example: Robbin Williams, Jim Carry, most comedians.

I'm as clueless as you are. For me it would be impossible to act happy when I am not. The most I could do is a neutral face. Maybe their overall philosophy is fake it till you make it.

Sometimes it is. If you’re taught that your feelings are not important you stop sharing them and hide behind a smile.

I think so. I think they are people who were met with annoyance, anger, or disgust by their parents if they were anything BUT a positive presence. Maybe these people were even parentified as children… expected to help make a parent(s) feel better constantly?

Just some guesses/ideas in my mind

I never completely understood it either as it's not something I do.

Could be their armor / protection as don't want to seem weak or be embarrassed? Maybe it's unhealthy suppression of real feelings they don't want to feel or accept.