Rebel.......there are several factors causing low self esteem. I would consider the following to be the major ones:
1. Low number of successes in life, whether it be in sports, job, money, friends, etc. etc...
2. The people you associate with. Perhaps some of them are low toned, some might be negative, some may be sorta lost themselves,.....etc...
3. The content of your REactive Mind, which is well explained in the book
Dianetics. The Reactive Mind, which Freud called the subconscious, is that part of the mind where are stored your experiences of pain, fear, loss, suffering, unconsciousness, abuse...etc. etc...which are all mostly hidden within your Reactive Mind, but which can take control over your emotions, your health, your thinking.
4. Watching too much TV, which if you consider it carefully is of low intelligence, full of negative news, false data, blaring advertising, sex and violence..........all of which ----and here's the crucial point------you are
recording and carrying around with you.
5. Personal programming which is the result of training, rearing, and education from those around you in your formative years.
There are other factors, but these play a major part.
Ponder these over and you'll hopefully you'll come to a decison to
TAKE CHARGE OF YOUR LIFE, BECOME MORE CAUSATIVE, AND DISALLOW OTHERS TO LEAD YOU INTO THE WILDERNESS.
Good luck.