Mocking birds never hurt people, they sing，they dance and they bring joy to you. Boo Radley, Tom Robinson, they never tried to do harm to anybody but were treated as weirdo, jerk and the last person people wanted to approach.
Atticus Finch, an impartial judge, set himself as a example for his kids, James and scout, telling them to open their minds to Boo Radley. He used to be imprisoned in his own shelter. And it turned out that it was Radley that played a vital role in saving the two little adorable things' life at stake.
When everyone despised Tom for his being a rapist, Atticus Finch still defended for him believing people should never judge a person by appearances, whether they are black or white. Although the jury convicted Tom was guilty, you have to admit Finch had made great strides in creating a more equitable order of the court.
The world won't change a bit if you stay where you are but it can be a better one as long as you are endeavoring to make it.