When a person realises that he does not fit set standards, he starts to feel self deficient. But to compare to what? Ask yourself: do you want to be just as everyone else or be yourself? You can't be yourself by trying to hide your imperfections. You can achieve this by developing your virtues. Any imperfection can be counterbalanced by the virtues, which apply to you. Lack of beauty can be compensated by charm. Physical imperfections may be compensated by self-confidence. If you are not a good speaker, you can compensate this by being a good listener. And for someone who is shy, only one advice can be given: save this precious quality as a treasure. A shy person has got a hidden charm, in case if you do not try to play as a 'cool' one.
The feeling of self deficiency is based on comparison: not only that I am an unattractive person, I have got no talents and capabilities, I am not intelligent and cute and communicative, and therefore do not deserve this and that... But there is something more: I am much worse to compare with them. This is a dependency relation in its pure manifestation. And therefore, the polarisation is created: they are good and I am bad.
This polarisation creates the equilibrium powers, which in turn make a person want to rise artificially lowered best abilities and features. Therefore, it turns out that a person doesn’t behave in his usual way, showing off what he intends to hide. And this effort to hide imperfectness has a more harmful effect to compare with the actual imperfectness. There is only one way to get rid of any imperfection: to stop comparing yourself to the rest and put an intention vector from imperfections to perfections. Create yourself a positive slide which shows off your perfections in such a way that your imperfections are not visible. Virtually live in this slide and it will become a reality.