It's an ego thing. Lent it is a forty-day period of reflection, consideration and repentance. It is a special time when we should look into ourselves to see what we can find that we should amend. The easy answer is sin. Of course that is true.
Sin is easy to recognize.
It's big and mean and ugly. We go to Church every week or just about every week. We read scripture. We can see the speck in our neighbor's eye, but too often we miss the beam in our own. That may constitute arrogance.