One of the biggest dangers of becoming a good man is when you actually view yourself as a good man. Yes, I know this comment sounds contradictory, but hear me out. It is more common that what you think.
The more good you try to do, the more you grow, and the more you stand up against self-contentedness and petty behavior, the more people will recognize it. After a while you will find yourself surrounded with like-minded individuals. You will help each other grow as people. And that’s when the real danger begins. You will think that your actions are correct and your mindset is proper, simply by social acceptance and praise.
The same will happen to the way you view your enemies, the social injustices you challenge. You will automatically view them as simple acts of petty men, and dismiss them as wrong, and as proof that your path is better. You, at this point, risk being blinded you your own righteousness. And blind righteousness is just as dangerous as pettiness because it is born from self-contentedness.
Even the most self-centered man believes in what he does as right the same way that the most righteous man must always question his actions and his motives. Are you doing good, or just what "good people" want you to do? Do you condemn someone because of their actions or are you condemning just because you are supposed to condemn them? Do you do the same thing you criticize?
We see it every day, people passing judgments just to feel superior. We see people rallying against someone just because having a common enemy give them a purpose. This is not righteousness, this is being a sheep.