Part of that is how friendly they are. Part is how pretty they are. Part is how smart they are and how able they are to help others. But part is how much they can afford to throw fancy parties, go to expensive schools, or get good health treatments.
The more friends you have, and the more friends your friends have, the more you can get done in society. If you want to start a business, get elected, or other things that require a lot of other people’s support, having lots of friends helps.
Sure it’s not fair. What you can do is figure out how to be a good friend to those around you and work well with others. This includes things called “allyship” and “solidarity” as well as just being nice to people and having useful skills.