Even balanced, well-adjusted normal young people hate themselves. They haven't been around long enough to become fully accustomed to their own faults. Their faults, like their bodies, are new. It's like the experience pubescent teenagers have where they look in the mirror and see, for a brief instant, a grown person that seems like someone else. When you're young, your faults protrude like ripened fruits. After years of disappearing and reappearing in slightly different forms, your tendencies and faults become accepted and invisible like the shape of your nose.

It also stands to reason that people can accept other's tendencies and faults in the same way that, after a long enough period, they accept their own moles and warts. Longtime married couples probably.