Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
On the one hand, Bigger is a thoroughly dislikeable character. Even though we recognize that it is not his fault that he’s poor, and we recognize that circumstances have created his tendency towards crime, he’s a manipulative bully. He’s mean to his little sister, mean to his friends, and mean to his girlfriend. Ultimately, however, though we don’t like Bigger, we are sympathetic to the position he’s in. This is achieved in large part by a narrator who explains how shame and fear dominate Bigger’s life, causing him to act the way he does.