Is it any accident that the official liturgy begins with Kyrie, Eleison? It is the most common Christian short prayer, which is some form of "Have mercy on me!" In time, I have come to see how important this prayer is. It is at the heart of the classic Jesus Prayer, "Lord Jesus Christ, have mercy on me a sinner," which the Eastern monks recited nonstop whenever possible.
This is not a self-demeaning prayer, nor a self-defeating prayer, nor is it a disempowering prayer. Relying upon mercy, in fact, protects you from the arrogance and pride that wants to judge others, even in your mind. It situates you in freedom from any sense of your own sufficiency or superiority, and affirms a non-need to justify yourself, and thus keeps your heart open for others and for God. It is basically a prayer for detachment from the self, both mind and heart, and its endless games of self-validation. "Lord, have mercy" seeks validation only from God and not from any inner or outer attempts to be worthy, independently "good," or not-in-need-of-mercy.
Note that when you do not stand under the mercy, your mind almost certainly does one or all of three things: plays the victim, accuses others, or falsely exalts itself. When you honestly ask for mercy, you make all three of these responses unnecessary and, in a way, impossible.
"Lord, have mercy" makes your identity a totally received one (Just like the persons of the Trinity), a gift of grace, and nothing that you need to protect or can claim as your own.