I think, if the leader of a Christian worship service called, "Will the worst sinner please stand up?", that invitation ought to have the same effect as the phrase, "Let the congregation please rise." Everyone should come readily to his or her feet.
When we consider sin in general, it is easy to look around at society and see the unjust systems with obscene levels of sin on the national and international levels. In comparison with these outrageous sins, our own sins can be made to seem paltry, beneath notice, unworthy of mention. This is election season; repentance often is just a misnomer for mudslinging when the sins identified are always someone else's. It is tempting for us to discuss sin as if our own worst sin is to be inextricably trapped in an unjust system of someone else's making, tainted by someone else's sin which we loathe, blind to our own sins with which we are as unhealthily comfortable as a baby with a loaded diaper.
One pastor taught me this, which has blessed me for years: if ever I should be tempted to see sin as someone else's problem, to discuss sin but identify the worst of sinners as someone else, I have left behind grace. St Paul once identified himself as the worst of sinners. It would even be convenient for us to agree with Paul, not that "I" am the worst of sinners, but that he was the worst of sinners. St Paul had the right spirit and attitude on this: that the first sin we should condemn is always our own. As Jesus said, first we should get the log out of our own eyes. If our confession is, "Lord, I regret that I am caught up in someone else's sins and haven't done enough to stop other people -- you know, the detestable ones -- from sinning" -- then that is no confession at all. As Luther once said to Melanchthon: you have real sins and you are a real sinner; be glad, because real sins are the only kind of sins that God forgives.