Some people don't intuitively 'connect' with other people around them. There are lots of reasons why it could be, so it doesn't automatically mean someone is a 'good' or 'bad' person, but it obviously will hurt their ability to make friends or meet a partner. In some cases, these people don't even necessarily care very much and are happy by themselves. In other cases, they might care a lot but pretend they don't. There are lots of different types and reasons, but they all have this this one thing in common, that they struggle to intuitively and authentically 'connect' with people around them.
For those who have some very unique qualities, are extremely good looking, or from a wealthy background, or very talented at something specific, they will probably be 'successful' in attracting people and partners, but will nonetheless often struggle with growing, maintaining and holding onto those relationships.
Ask yourself a simple question... what is going through your head when you are talking to someone? Are you:
a) mostly thinking about them and are genuinely interested in finding out more about them?, or
b) mostly self-conscious, thinking about yourself & how to ask the next question without sounding 'stupid'?
If it's b), then that demonstrates a major symptom of what your problem is: you aren't actually connecting with other people. Your insecure mindset in conversations is likely causing you to come across self-centered without you even realising this. Most people can probably relate to this at some point, because nobody is perfect. It is relatable, and if you can find a way to acknowledge this when you are with other people, instead of somehow denying it or pretending you are not self-conscious when you actually are, then other people will start to find you more relatable as well. ... and you will come across the odd ar.sehole who sees it as an opportunity to f**k with you instead, although most people aren't sociopaths, so this will be a small %.
Many people make harmless jokes about these kinds of insecurities among each other. It's a large part of how they 'connect'. If you try to repress these insecurities instead... you're really shooting yourself in the foot hard. Not only you don't 'connect', you also make the problem worse at the same time, and come across as insular and emotionally immature, further exasperating your existing insecurities.