I can see your point on how fake people are here, putting on masks and faking smiles, etc...

As a teen, we visited New Zealand a couple times. There is a HUGE difference in the warmth there than here. I felt like the people in New Zealand were far more genuine in their salutatioms and overall demeanor than people are here. I suppose here, it feels more obligatory. It feels like people almost mutter to themselves in their heads (omg, i gotta smile now)"when seeing a person approaching into their space and are forced to put on a jolly smile. In New Zealand, I didn't get that impression. The genuine scope of their friendliness not only came out of their mouths, but also very much showed in their eyes as well as their posture. Theywwouldn't just ramble the obligatory hello and look straight at the floor afterwards, but they would hold their eye contact.

I'm sorry you've experienced this culture shock. I don't know what to tell you on how to handle it. I suppose you will get used to it in a way. If you are a friendly person by nature, just keep being yourself around people. Maybe they can learn something from you