There are many discouraging things that happen in To Kill a Mockingbird by Harper Lee, including ugly examples of racism and prejudice. Some people lie, other people are mean, and too many people do not treat others as equal human beings in this novel; however, there are some things which are encouraging, as well.
First of all, we have to remember that not everyone in town demonstrates prejudice; in fact, some of them even take positive action against racism. Judge Taylor, for example, does his part to save an innocent black man (Tom Robinson) from being sent to prison--or worse--by assigning the case to Atticus and by his careful attention at the trial (despite how he looks sometimes). B.B. Underwood claims to despise blacks, yet he is prepared to defend Tom Robinson from vigilante justice. Tom is willing to help a white woman because he thinks she is lonely and needs his help, despite the potential risk to himself. The Reverend Sykes and nearly all of his congregation love and appreciate Atticus and his children for doing the right thing. And of course, Atticus does the unthinkable--actually defends a black man in court because he knows Tom is innocent. There are good people who are willing to look past color and see people just as people.
Second of all, Scout and Jem represent the next generation in Maycomb, and they are learning valuable lessons about people and skin color and life through the course of this novel. Atticus has taught them that courage is more than a gun or physical ability through their interaction with Mrs. Henry Lafayette Dubose; he has taught them that it is a sin to kill a mockingbird (they must protect those who cannot protect themselves); and he has taught them that they must see things from other people's perspectives, to "climb inside of his skin and walk around in it."
He has also taught them specifically that treating a black person as someone inferior is wrong. He is clear and specific when he says:
“As you grow older, you'll see white men cheat black men every day of your life, but let me tell you something and don't you forget it--whenever a white man does that to a black man, no matter who he is, how rich he is, or how fine a family he comes from, he is trash.”
Atticus does not allow Scout to use the "n-word" and tells his children by his own actions that every person has value, regardless of color )like Tom Robinson) or money (like the Cunninghams). The fact that Scout and Jem seem to understand this and agree that injustice is wrong gives us hope for the future.
Finally, the justice system does seem to be changing. A judge who does whatever he can to make sure an innocent man is not unjustly convicted, despite the fact that he is not successful, is a positive change. When a lawyer believes his client is innocent rather than just takes a white woman's word over a black man's, society is on the verge of change. Even better, when a jury is not unanimous about convicting a black man just because he is black, there is reason to be optimistic about the future. When Walter Cunningham's father chooses to cast his vote for the facts rather than for a long-held prejudice, there is hope that others will one day do the same--and soon.
So, despite the moments of ugliness we see in some people and their actions and attitudes in this novel, we have plenty of significant and real reasons to feel encouraged about a future in which people will be treated equally in all circumstances and be free from persecution.