A human has a very complicated psyche, we are the product of years of evolution teaching us to adapt, seek protection as we constantly seek for human connection for survival. Our minds are very much wired to be affected by our surroundings, as we constantly seek external validation, every aspect of our surrounding some way or the other affects the way we think. It is although not always bad, everything has some disadvantages, that is, living in a society is important but they can be a source of our insecurities.
As an infant the way you are treated by your guardian and others that you trust shapes the way you treat and expect from other individuals. A point to note here is, no human is perfect just like you everyone has insecurities that limit them to achieve something, to celebrate anything and themselves. The people around you are also not very different, they are in fact like you, a product of our society.
At the age when you start developing abstract thinking and try to discover your identity asking yourself who you are, often these insecurities come in the way and manipulate you to be the person which is the "most appropriate to be" in a situation, under the calculation of your insecurities. The one you developed as a coping mechanism to fight/deal with your insecurity and problems becomes trouble in identifying your capabilities and your confidence. But again, it is a life process, no one can be perfect one has to go through this discovery of self, to see themselves beyond the limitations they have created for themselves.
To do so, first, one has to constantly communicate with themselves, meet their prior wounds, finding ways to look past them, solving the inner issues induced by them, and finally, if the wounds have no sign of healing can also take an external help of a therapist or even your loved once. Understanding and knowing yourself is the first step to your development. Polishing and constantly try to develop your skills, choosing the one you like to do the most so you never feel any burden to do any work.
Once you are over and healed from your wounds, you now are capable of judging your worth all by yourself and now can proceed with crossing your once drawn line of your comfort zone and expand it to be a better you. Apart from ourselves, the limitations can be the current society that you live in, but with the true understanding of oneself can learn to ignore and walk with utmost pride in achieving, losing, trying new things as one like.