Dallas Willard’s thoughts on this particular part of the prayer get right to the point:
Today even many Christian read and say “forgive us our trespasses” as “give me a break.” In the typically late-twentieth century manner, this saves the ego and its egotism. “I am not a sinner, I just need a break!” But no, I need more than a break. I need pity because of who I am. I my pride is untouched when I pray for forgiveness, I have not prayed for forgiveness. I don’t even understand it.
We are still this way. We just don’t like to admit our condition. It is “offensive” in some way to discuss things as “sin.” It’s almost like we pray, “Could you help me get past this little quirk of mine?”
But we need pity. We need the incredible grace of God touching us as we feel the pain of our failure. We don’t need minor adjustments. We need a complete overhaul.