While self-depreciation can become unhealthy at huge amounts but the problem is when man becomes obsessed with one's self. The problem of this self-esteem movement is that the more you think nothing is wrong with you, the more praise yourself and love yourself, the more you are to receive positive reinforcement from the Devil. What happens is that the more a person is obsessed with himself, the more the person says, "I do not need Jesus. I am fine the way I am."
This creates the problem of being self-serving. When it comes to the Christian life, you cannot serve two masters. The problem of "loving one's self" is nothing more than me, myself and I rather than God loves me and I love Him. This means doing good works of righteousness for one's own publicity rather than for the glory of God. The more I think of myself, the more I am frightened to see that I am nothing more than a Hell-deserving sinner. When I see myself doing good works because I love the LORD - it is not me but Christ working in me. Philippians 2:13 says that it is God that works in the believer.
Christians should not get positive reinforcement from their flesh. Jeremiah 17:9 says that the heart is deceitful above all things and it cannot be trusted. If Christians want to have positive reinforcement then it is not about themselves but rather that they are saved in Christ. I refuse to affirm myself of my "positive attributes". Instead, I choose to look at the fact that I am a sinner saved by grace, that it was the mercy of God that saved me and I had nothing to do with my salvation except to believe in faith on the Lord Jesus Christ.