Friends are good for your immune system
I have around less than 10 close friends additional to my closest family. Even while I meet a lot of interesting new people I see myself always finding my way back to these certain people, a group from childhood and few other friends.
Evolutionary psychologist at the University of Oxford, Dr. Robin Dunbar has found from his research that when you are laughing with your good friend or feeling his/her friendly pat on your back your body releases endorphins, these feel-good neuropeptides boost also your immune system and protect you from disease. It's important to surround yourself with people who make you feel loved and give the love back to them, not just for your mental health, but also for physical health.
The real friends that you hug and laugh and talk your deepest thoughts to have a great impact on your health and happiness. People need 3-5 of these kinds of friends for optimal well-being. Social media network with people who are not really there for your life don't have this kind of effect. Dunbar also has found out that human brain can't hold close connection to more than about 150 people and from these about 15 people are the most crucial for you to live a good healthy life.
To create new friendships when school is over and you have one steady job might be tricky. I have project based jobs, so I always meet new people, but I rarely make friends with my workmates. I have had a bad experience while mixing work and fun, so I keep these mostly apart. I make friends where ever by talking to people, asking questions, being interested. Generally everybody wants to find good friends. Some friendships last longer some not, some people go, some stay.
It's important to have friends that have different viewpoints of life, it helps to understand people better in general. We all have the same needs, but we find our way towards these needs on different paths. Some of my closest friends have very different viewpoints of life, also different jobs and family situations. But that is something that makes our friendship rich, I can always hear an opinion that is out of my own little world.
When I look back the only true clashes I have had with some friends, have been about different kind of moral, if someone close to me has different view about what is wrong and right I have been broken-hearted and disappointed. It might have been just a small act, but have had a big meaning to me. I want to believe that people are good-hearted. I have ended three friendships because I have found out that our moral is very different and I wouldn't feel healthy in that kind of friendship.
I haven't been an angel either, I have hurt some of my closest friends. Some happened years ago, and some last year. I never wanted to hurt them, but life happens. We are lucky that we still all have very strong friendships and maybe it even reminded us to keep it safe.
I love you and I will always be on your side. You know whom you are.