I don't know how many times I've heard the question asked. It is most often used when someone oversteps their authority, or offends someone with a word or deed that is interpreted as presumptuous. More often than not, the question is asked in a defensive or corrective manner.
"Who do you think you are?"
But when asked introspectively, honestly, and deeply, this question is one of the most profound and potentially impactful on any of us. Why?
Because, your answer to it explains you. It explains your behaviors, your self-talk, your habits, your inclinations, what you do when you are angry, or when you have free time, or when you get honked at for no good reason. It explains how you view God, how you think you should practice (or not practice) religion, and how you walk through this world among men.
Who you think you are is of utmost importance to God.
Right at the very first of his very first teaching to his very first students, in the speech that gives context to the rest of his teaching for the rest of his life, Jesus describes the kind of people his people should be. And he ends this identity speech with a proclamation of your identity by saying, "You are the light of the world." (Matthew 5:14)
Listen, anytime Jesus says you are something, you need to listen. He knows who you are, and when your answer to the question of who you think you are lines up with who he says you are, you will finally - finally - be right.