If you, God, kept records on wrongdoings, who would stand a chance? As it turns out, forgiveness is your habit, and that's why you're worshiped. Psalm 130:3-4 (MSG)
Part of my job is analyzing phone calls that people take as part of their Customer Service job, and then coaching them on how they can improve (a la "your call may be monitored to ensure quality service"). When I go into the coaching sessions, I never cease to be amazed at how hard people are on themselves. It's rare that I have to convince somebody they can do a better job. Most often, people criticize their own performance far more mercilessly than I ever would. Most of us are hurtfully self-critical.
I've discovered the same thing to be true when talking to people about their faith journey. Many of us, deep down, are so convinced that the balance sheet of wrong doings to good deeds is so heavily weighted towards the wrong doings that we're convinced God wants nothing to do with us. "You don't know what I've done," is a phrase I've heard a time or two. I've uttered it a few times myself.
On one hand, our natural inclination is correct. If God judged us based on our balance sheet, not one of us would stand a chance. However, when God's message tells us about Jesus dying for our sins, it simply means that He paid the price for our wrong doings. If you will believe Him, God makes a habit of tearing out the negative side of our balance sheet and tossing it in the incinerator.
I'm sure he's surprised when we keep bringing up the subject.