People like extroverts because they appear to wear their internal lives on the outside, thereby making them seem easy to figure out. Extroverts tend to talk a lot. Introverts require work and thought to find out what it takes to manipulate and use them, and people are lazy and stupid. People want social activity without work and without having to second-guess themselves.
If you can convince people that you are happy all the time they will automatically like you because then they don’t have to be reminded of reality all the time. People like being bullshitted if you can pull it off well. You seem happy, therefore by a process of herd-osmosis they feel happy too.