I have too many friends. I know, I’m Mr. Popular, right? Not quite. Most of my “friends” aren’t friends. I’ve simply accumulated a hefty list of people on Facebook , Twitter, Instagram and elsewhere. Staying “friends” with people who are no longer (or were never) my real friends always seemed harmless, but it’s actually ruining my social life.

For starters, having all those friends was a security risk. Prior to 2015, they could dispense my information to Cambridge Analytica and other shady data collectors. Your associations tell social networks—and advertisers—an awful lot about you. Just as problematic, all those pseudo-friends and likes distract from the actual potential of social networks. We’re all starting to realize that algorithmically driven social networks can’t be trusted to deliver accurate, useful information from real people you care about.

It also turns out there’s a maximum number of people you can maintain relationships with at any given time. That number is about 150, known as Dunbar’s Number—after Robin Dunbar, the University of Oxford professor who discovered the pattern researching how primates act in groups. In the world of Homo sapiens, Prof. Dunbar again and again finds examples of people naturally finding groups of about 150.

Online, strangers lurk. The average Facebook user has 338 friends, according to a 2014 Pew Research Center study. And don’t forget your Snapchat pals, everyone in your Twitter DMs and Instagram comments, your LinkedIn connections and your WhatsApp contacts.

At first, some thought these social networks might help everyone keep tabs on more people than ever. Prof. Dunbar says that’s true, but it isn’t to be confused with friendship. Social networking can prevent a mostly forgotten friend from becoming completely forgotten, but skimming your news feed does not a friendship make.