There is a difference between self-esteem and self-opinion.
Don’t be afraid to coach yourself, but remember the difference between self-coaching and self-flagellation. Unless your sins are awful enough to warrant cruel and unusual punishment, you should never cross the line between self-correction and self-abuse. For example, a child-rapist has every reason to abuse himself — but a person who earns a C in biology does not. A person who merely “does not fit in” certainly has no reason to hate himself on that basis alone, and he may even be justified in feeling good about it.
We often fail to appreciate the difference between self-criticism (i.e. self-coaching) on the one hand, and self-abuse on the other hand. This leads to a common, yet counterfeit notion of self-esteem, wherein a person is taken to have high self-esteem so long as he appears impervious to ego challenges. The most pernicious thing about this counterfeit notion is that it allows those with the lowest imaginable self-esteem to maintain a high self-opinion, which is not at all the same thing.
Self-opinion (by my definition) is what we tell ourselves about ourselves. It is a rationalization. It is essentially a concocted narrative. Self-esteem, on the other hand, is (by my definition) not based upon thoughts or narratives. It is based upon a deep and abiding instinct for healthy self-prioritization. Think of it this way: House cats typically have extremely high self-esteem, but they are incapable of having a self-opinion at all. In perfectly healthy people, self-opinion is rooted in self-esteem — but in less-than-healthy people, self-opinion may very well be rooted in fear and insecurity. This insecurity is in all of us unless and until we seek our true spiritual identity — the identity that transcends materiality, time, ego, and even death. Insecurity, which is tantamount to low self-esteem, is natural and unavoidable when everything you recognize as “you” is in a state of perpetual decay. And make no mistake about it: Insofar as you are a time-bound hunk of flesh, you are definitely in a perpetual state of decay. You are, as it were, “a flash in the pan,” so upon what basis could you possibly esteem yourself as anything more than a flash in the pan? You can't — not of yourself, anyhow. In fact, you can develop self-esteem on only one basis:
A realization that you are a child of God.
That is a metaphor, of course, as all religious-speak is. Think of it in any way you like. Perhaps you are an appendage of the Ultimate. Perhaps you are a part of the Great Circle of Life. Whatever. The point is that your self-esteem cannot rest on your “self" any more than the Empire State Building can rest on a toothpick. Your "self" is so weak, so tiny, and so contingent that it does not, and cannot, be the basis for its own value. The denial of this reality is the ultimate folly, and the ultimate sin.
You cannot find value in yourself and of yourself. You can only find value by recognizing your innate dignity as part of the Grand Ultimate of All, which I call God, and which I relate to as a person. If you attempt to base your self-opinion on anything less, all you can do is concoct a thin rationalization in the face of your inevitable demise — a demise that is already well underway.