Hoofprints And Hooves

Here we go.
Those who suffers from low self esteem, a poor self image carry around reasons "WHY" they deserve misery. I use the metaphor of 'little hammers'. They have a collection of little hammers with which to hit, to knock themselves down.
They will grasp on to any hammer within reach. And they keep them inside, close at hand.
Examples-"I'm fat!" (hammer 1) "I'm ugly!" (hammer 2) "No one likes me!" (three).
The person might actually be thin, beautiful and popular, but those are the hammers that he or she will pound themselves with because they will never be thin enough, pretty enough or popular enough.
If, by some miracle, they do toss away one of their little hammers...they still have the others, and may pick up the dropped one at any time.
The heart of it is finding justification for feeling so critical about themselves. 
A well integrated personality does not suffer from low self esteem-they assess themselves clearly, accepting that they have good and bad qualities, just as we all do.
A well integrated personality can handle criticism, accept responsibility for their actions because their egos are not threatened. I call it rhinoceros skin.
A person with low self esteem will see any criticism from others as a nearly mortal blow to their ego-so they have created a defense mechanism: nothing is their fault, everything that happens is because someone else did something bad. They can't handle an ounce of criticism.
Are those with low self esteem doomed to a lifetime of little hammers?
No.
Everyone goes through those phases, and the first step towards earning your rhinoceros skin is to toss away your hammers. Don't treat yourself so poorly. Accept that you are a person of value, someone who will, yes, make mistakes, but also someone who will achieve goals and do good.
If you do screw up...resist the temptation to pick up that hammer. Instead:
"Yup-I blew that. Not the end of the world." And then move on.