"You can't judge me" is like a 21st Century catchphrase. Despite saying it, we don't act like it's true. We make other people into our little "judges" and then try to please them, evaluating what we do based on what they will think. Whether it's a parent, boss, friend or colleague, we do things in a way to get the approval of our judge or judges. If they don't approve, then we either modify our behaviour or pull out the "nobody can judge me" line and then find another judge with different standards!
Jesus makes it very clear that He will be the judge of every person who has ever lived. He has the authority to judge because He created us, we belong to Him and are accountable to Him. As human "judges" we tend to hold people to standards that we can't keep ourselves, but Jesus lived a perfect life as a man, encoutnering every temptation and difficulty that we do, but without sin. Every one of us has some bias that leads us to judge people and circumstances in different ways, but Jesus is the perfectly fair, unbiased, just judge. We might try and ignore it, or talk ourselves out of it, but the reality is that Jesus has the authority to judge, He will judge us fairly, and we will fall far short of the perfect standard required.
This would be terrible news if it wasn't for the fact that Jesus is not only the judge, but the justifier. At the cross, our sin is exchanged for his righteousness. There is justice, as our sin was punished, but there is mercy, as Jesus took that on our behalf! Trying to convince ourselves that nobody can judge, while we try and justify ourselves in the eyes of other people is not good news. The good news is that the real judge has justified us!