Why do people always feel like they're not good enough in one way or another?

Sometimes I sit and wonder what causes insecurities in different people. Why do some people have more insecurities than others? Is it due to expectations depicted by the media? Is it due to the words that people choose to use on these individuals? Is there a person in this 6 billion people on earth that has ZERO insecurities? Or are insecurities something that plague EVERY single individual?

Compensation

Insecurities drive people to do all sorts of things to compensate for the feeling of being "not enough". Some people cover it up with material goods like cars or branded clothing, some cover it up with some form of fake confidence. Some people over-compensate by being a serial dater.

At the end of the day, what do these compensations accomplish? If I were to imagine stripping the effects of these compensations down to it's raw-est form. It's just to show the world that you are something that you want people to think you are. So once again it boils down to a fear that people will think about you negatively about a certain aspect. Could it be because that trait/aspect of you means something to you and you're afraid that by having people "shit on it", it's going to hurt you?

Are insecurities what helps us to feel human?

I remember watching a snippet of Ellen where Anne Hathaway was talking about her movie and how she was insecure about her body after having a child. A gorgeous actress with a beautiful smile, insecure about how she looks?!

Another instance of this "wow" was when I watched the BTS of The Greatest Showman. Someone as talented as Keala Settle, that sings with so much heart, have performed on Broadway for years, is nervous and slightly insecure about how she sounds?! You gotta be kidding me!

That was really like a "oh wow, celebrities are humans too" moment. We often forget that these high-profile figures fight these same stupid demons that people like you and I encounter daily.

Conclusion

Thus it really made me think, is there a purpose for insecurities on a biological level maybe? Is it a mechanism that we've developed so that we'll always strive to grow instead of just resting on our laurels?

Often these things we're insecure about are significant enough to us and that's why it's even something we're afraid might not be good enough. I think no matter how comfortable you are in your own skin, there's bound to be something that you're still unsure about.

Is the solution then to just suck it up, and try our best to improve on it?

Will we ever reach a point of "no insecurities"?

Does it really matter in the end?