Atticus Finch rarely makes negative comments about anyone in To Kill a Mockingbird, but early in the story he reveals that the Ewell family has been
... the disgrace of Maycomb for three generations.
During the trial, Bob identifies Tom by pointing at him and telling the Judge
"--I seen that black nigger yonder ruttin' on my Mayella."
Atticus's queries of Mayella brought out many facts about Bob that had not been uncovered during the prosecutor's questioning. Scout, and the jury, learned that Bob's
... relief check was far from enough to feed the family, and there was strong suspicion that Papa drank it up anyway--he sometimes went off in the swamp for days and came home sick... the younger children had perpetual colds and suffered from chronic ground-itch...
After Bob has spit in his face, Atticus tries to explain to Jem that the man had little recourse.
"I destroyed his last bit of credibility at the trial, if he had any to begin with. The man had to have some kind of comeback, his kind always does. So if spitting in my face and threatening me saved Mayella Ewell one extra beating, that's something I'll gladly take. He had to take it out on somebody, and I'd rather it be me than that household of children out there."
Bob was not through with his harrassment, however. After learning of Tom Robinson's death, Bob stated that
... it made one down and about two more to go.
After losing his job with the WPA "for laziness," he blamed Atticus for it. After attempting to break into Judge Taylor's house, he turned his attentions to Tom's widow, who he stalked and frightened, "crooning foul words" as he followed her. After Bob's death, Sheriff Tate claimed that Boo's rescue of the children and killing of Bob was "a great service."