Another blessing of Romans 2:1 is that it helps you deal with troubled people.
When I taught Christian school, an occasional irate parent would become furious because their child had to obey the rules. I would listen in fascination to their accusations against me. Some were deadly accurate. Some were plain stupid. And all of them were delivered with the same facial expressions, tone of voice, and conviction. Roughly half the accusations were true.
But a different parent, acting the same way, would have a different list of accusations (There was some overlap, of course). I could see that the parents' accusations were all coming from the same source, but what was the source?
Romans 2:1 explains that the parents were describing their own sins, not mine. By the laws of chance, their accusations were sometimes true, but it was chance, not discernment.
So when a parent accused me of lying, I knew that the parent already knew the student was guilty and was lying. I quit trying to convince them that the student was guilty and would explain the need to keep classroom order, and it usually worked.
When a parent accused me of hating the student, I realized that the parent was bitter at the student's constant bad behavior at home. I would then talk about the need to be patient with the child, the necessity of presenting a united front, and some advice on dealing with teens.
Did it work? Less than half of all Christian school teachers entered their third year of teaching. I taught for ten.