Nearly everyone supposes themselves to be good, the exception being, the worst think of themselves as much better than they are and the best think of themselves as much worse than they are. Then there are the correct, which think of themselves as they actually are regardless of how good or bad, but they nearly always skew towards the good and best side, because discerning reality as it is is not a task evil prefers to engage in except when it stands to gain them power or control.
The problem for civilized society is, more the same now than it always was: not can you? but: should you? When you are tasked with maintaining order or at least maintaining peace, how violent ao deceptive are you willing to be against the greater good and does that bring the best outcome for the most number? Do you know the consequences? Can you see all sides?