Neither Self-esteem nor Self-loathing
Humility does not require we think poorly of ourselves, nor be given over to self-loathing. Just as we must not be over-lauding ourselves, we must not sink into a state of self-loathing, for both states have their basis the ego. I would be the last person to suggest anyone be trapped in a state of self-hatred, or wallowing in the mire of low self-esteem. I am rather concerned for those who are drawn into the sin of pride, which is the result of a false attempt at self-esteem. Feeling good about yourself is not the same as being puffed up with pride.
C.S. Lewis wrote that it is not wrong or sinful for a pretty woman to look in a mirror and notice she possesses beauty, but it is better that she should walk away and forget about it. In the same way, it is not pride that leads us to notice we have a special gift as a musician, a writer, an orator, or are good with children. What is important as a Christian, is to give thanks to God for our gifts, while turning our face towards Christ with gratitude, thankful for the opportunity to use our gifts in service to God and our neighbor.
When we possess a healthy humility, we are neither filled with self-loathing, nor over-lauding, but immersing our self in service to the God who has created us as we are. We do not stand like the Pharisee, giving thanks that we are not like other men, but, like the Publican, we stand before God, in all our nakedness, asking to be made whole. We confess before the Lord our unworthiness, yet give thanks for the status we have as his children. We are a royal people, delivered from our sin and death by a Savior who came down as a servant.
I was a practicing psychotherapist for many years, before becoming a monk. It is sometimes good for people to see a psychologist, and I have recommended such, over the years. However, the problem with psychology is to be found in its humanistic base. Orthodoxy psychotherapy, as expounded so beautifully by Metropolitan Hierotheos (Vlachos) in his book by the same name, is far superior for bringing about healing.