People with low self esteem tend to make excuses for everything they do. That's why their brains tell them lies about what they can or what they cannot do. These fake excuses prevent them from doing things that are good for them.
Let's see some of the most common lies that our brains tell us:
1) Others can do better than me
People who are afraid of trying to become successful tend to think that others are better than them. That's not only a lie, but it also prevents them from trying and from doing things. For example, a person with low self esteem won't go to an interview because he/she will think that he would never get a good job since there are so many others who would fight for it. But that's not true. Every single person on Earth has the same basic chances in life as anyone else. What makes the difference between success and failure is effort, push and attentiveness.
2) I can't live without my significant other
People who can find happiness being on their own, will never end up happy with anyone. They are depended to others, not because of pure love, but because they can't love themselves for who they are. When they do love themselves, then they will understand that, first of all, they need to be happy on their own. If they are, they are capable of creating a fulfilling relationship.
3) Life is sad and unfair
Pessimism is caused by lack of self confidence. People who are full of insecurities tend to blame others for everything bad that happens to them. By "others" I mean life, god or other people. That's why they tend to believe that life is actually unfair and they don't recognize that our choices are responsible for who we are. Only major matter such as death are out of our reach, but still, nothing is unfair. It's just life, with its ups and downs.
4) There's no need to try
If you try, there is a possibility that you won't succeed. If you stop trying, then you've already failed! Giving up will only make you sad. On the other side, failure is something natural. Don't ever forget your goals - if they were meant to be easy to get, they wouldn't be called "goals". You need to try. As Samuel Beckett said: "Try again. Fail again. Fail better".
5) It's too late
Actually it's never too late for anything. You could always find a new job, love a new person or start a new hobby, no matter what your age is. You only need courage to realize that everyone's got their chance to try again and again. Life is never over until it's actually over.
6) I'm useless
No, you're not. Nobody is useless. People are just different. They have different traits. You might be capable of doing things that others can't even imagine. You only need to believe in yourself. This will be the beginning of you becoming a better, self confident person.