There are so many people, that it's impossible to get to know everyone intimately. But, each human expresses some archetypes, which is important because recognising the archetype(s) of people can give us clues for how to behave around them to get what we want, which is usually just a merry time, but this can also be used during times when you want to seal a business deal, attract a partner, etc. Can you think of any more?
For example, if you met a store clerk who was an elderly women, you would interact with her differently than if she was a sexy young woman. It would make sense to treat the clerk with respect, like she is your grandmother- she's probably some's grandmother. What archetypes do you represent? Experiment with adjusting your view of other archetypes accordingly. For example, I've become a man in the last few years, and each child seems more to me like a nieces and nephews than ever before, thus I act accordingly around them.
This archetype stuff can get very fine-grain, as there are an endless amount of things we could call an archetype. For example, today I met a store clerk who was an elderly man (age) (sex), who was English (nationality), who was reading a book (enjoys reading), who spoke to me about the days after WW2.
There are many different 'styles' of people. Many dislike having the attention being on them, probably because they’ve been burned in the past because of it. Think about reading in front of the clas for example- some people are rockstars while some people’s light is dulled.
Some people, like the young adult staff in hostels are comfortable with strangers because they see them coming and going all the time.
There are many different types of environment but only one you, and a change in environment can’t allow for a drop in mood, just because the environment changed.
As soon as you walk into a new room where there’s people, don’t just sit there quietly on your phone - unless it genuinely feels best - because it‘s likely that everyone will feel uncomfortable with your presence- maybe even you.