In Galatians 2:20, Paul is preaching a death to self. Paul said he was dead through what Jesus did. He experienced this death by simply counting on what had already happened through Jesus to be so (Romans 6:11).
There are people who have taken the "dying to self" doctrine to an extreme and, instead of being free of self, they are totally self-centered. They constantly think of self. It may be in all negative terms, but it is still self-centered. A truly humble person is one who is Christ-centered. Dying to self is not a hatred for self but rather a love of Jesus Christ more than self.
There are false religions that preach a denial of self. We need to be not just dead to self, but alive to God. A focus on the denial of self without taking on the power of Jesus Christ creates legalism. True humility is not a changing of self, or a hatred of self, or our accomplishments. It is simply an awareness that all we have and are is a gift of God. Only a person who acknowledges God can operate in true humility.