I don't know about you, but I don't feel like I'm the worst of sinners. I mean there are some pretty bad dudes out there. There are people who steal, kill, and lie but Paul says we should each consider ourselves the worst of all sinners. The truth is if we start thinking we're better than other people then we miss out on understanding the vastness of God's love.
In Luke 7 Jesus is anointed by a “sinful” woman. He tells onlookers that she loves so much because she's been forgiven so much. He even goes so far as to say that whoever is forgiven little only loves little (Luke 7:47). Considering that, it's pretty good news that we are each the worst of sinners.
Consider your sin for a moment. Make no excuses. Allow yourself to feel the weight of them.
Now consider that the creator of the universe died to wash you clean of these sins. You are clean and those sins are no longer a part of you. Allow yourself to feel the lightness, relief and freedom of that comes with forgiveness.