What is loneliness?

https://www.vox.com/2016/6/7/11844724/loneliness-explained

R: That’s so tragic. Why does it become harder to connect the longer you are lonely?

ML: There’s an interesting theory.

We depend on others to feel secure. When we feel lonely, we feel like there’s a permanent threat. It might not be a real threat, but we perceive things as threatening.

So what this amounts to when we’re in a normal, neutral social situation, we’re more likely to interpret the other person as being threatening. Someone might look at us in a neutral way, and the lonely person will think, “This person doesn’t like me.”