Why can't most people handle the fact that most people they know, don't care about them (except close friends, family, romantic partners)?

Most people including neighbors, classmates, people you work with, etc. don't care about you. These days if you quit your job, move away, etc. most of your neighbors/coworkers won't contact you at all/hardly. There are exceptions but for the most part. When you talk to people about this most stay quiet, play mental gymnastics, etc. And I'm talking about here in America.

Updates
4 mo
Many people may like you but it doesn't mean they care if you die or whatever or care that much.
Why can't most people handle the fact that most people they know, don't care about them (except close friends, family, romantic partners)?
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