There are a few comparisons that should be obvious. Sodom and Gomorrah must have been more wicked than first-century Capernaum - they were destroyed by a rain of fire and sulfur after all. The apostle Paul must have been less of a sinner than someone like Adolf Hitler. And for anyone who has read the Old Testament, the Southern Kingdom of Judah must have been a far more righteous place than the Northern Kingdom of Israel. For one thing, the Southern Kingdom at least had a few good kings, whereas the Northern Kingdom was completely spiritually and morally bankrupt from the day of its secession to the day it went into captivity to Assyria. But if these comparisons are true, then why in the world does the Bible state that the opposite is the case in each of these three examples?
And you, Capernaum, will you be exalted to heaven? You will be brought down to Hades. For if the mighty works done in you had been done in Sodom, it would have remained until this day. But I tell you that it will be more tolerable on the day of judgment for the land of Sodom than for you. (Matthew 11:23-24)
The saying is trustworthy and deserving of full acceptance, that Christ Jesus came into the world to save sinners, of whom I am the foremost. (Paul speaking in 1 Timothy 1:15)
And the LORD said to me, "Faithless Israel has shown herself more righteous than treacherous Judah. (Jeremiah 3:11)
What we miss when we make the opposite assumption is that the offense of sin gets greater the closer a person or a people walk with God. Those who flagrantly transgress the laws of God when they have never heard them are not nearly as culpable as those who flagrantly indulge in what they have heard forbidden. And to go deeper: those who sin in full knowledge of their wrong out of a hatred for God are still less culpable than those who love God and His Law and yet continue to offend Him.
It's just like that Biblical adage, "But the one who did not know, and did what deserved a beating, will receive a light beating. Everyone to whom much was given, of him much will be required, and from him to whom they entrusted much, they will demand the more" (Luke 12:48). Paul didn't just think he was the chief of sinners, he knew that he was because he had been entrusted with so much more than really anyone else at the time, and yet he continued to sin.
That's why I can't ever make myself feel better about my own sin by comparing my life to someone else's. If I compare myself to someone whose heart has not been changed by the Holy Spirit, then my sin will always be more grievous because I have been entrusted with far more than that person. If I compare myself to someone who I feel like is far greater than me spiritually, it doesn't really help to think that their lesser sins are more grievous to God. That thought doesn't stroke my fleshly confidence. "Haha! He is better than me, so that means he's in bigger trouble!" Nope. No good. Especially since it's those kinds of people that we want to become more and more like.
So who can we look to when we feel like a failure that will make us feel better? Well, that should be easy. We should look to Christ - not to compare ourselves to Him - but rather to see Him who is our righteousness. Paul says in 1 Corinthians 1:30, "And because of him you are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption." Ultimately, I don't have to compare my righteousness to anyone else's, because my own righteousness is not ever what counts. I have a stand-in. Christ became my righteousness, so my righteousness is perfection Himself. Praise be to God!