British Anthropologist and Professor at Oxford University Robin Dunbar proposed a theory called “Dunbar’s Number”. It posits that 150 is the average number of individuals with whom any one person can maintain stable relationships. Among this 150, only 5 will be able to maintain a close tie with you.
There was another post that echoed this: most people have an average of 155 Facebook friends; yet when we really need help, there are only about 4 people we would reach out to. The reason for this is simple: just like how humans can’t breathe in water, can’t run 100m in 2.5 seconds, and can’t see microwaves with our eyes—most people aren’t capable of maintaining more than a fixed number of friendships.
My suggestion is for you to take initiative with those whom you’d like to keep around. Focus your energy on those who are most likely to be close with you. Help others with sincerity, don’t expect rewards, don’t attach conditions to your friendship. Be willing to receive help, and show gratitude. Be willing to introduce your friends to each other, or asked to be introduced to others. Regularly spend time with friends and stay connected. Don’t pop up only when you need help.
“英国的人类学家，牛津大学的演化心理学教授Robin Dunbar发表了最为着名的”邓巴数字“（Dunbar’s Number）：每人交友（建立实质关系）的最大极限，平均是150位，且在这当中，真正能紧密维系的，大概也只有5位之多。