What makes it so hard to go down on one's knees (whether literally or figuratively) in order to ask for forgiveness, and mean it sincerely, is that you need to bring down your whole universe down along with you, and place it at the mercy at the one from whom you are asking pardon from. When you do this, you begin to actually feel the added weight not only of your offenses, but also that of the universe which you call yours. What makes it arduous at times is the uncertainty of whether that act of humility would be accepted or not. I am referring of course to human forgiveness. For God this would be enough, seen in His Goodness and Mercy. We men tend to complicate things a bit (if not way too much).
Pretty much another thing which shows that this world and this life is valley of tears.