The Bundrens are to the Southern U.S. what the Oedipus family is to Greece and the Hamlets are to Denmark: dysfunction, though not incestuous. By the time they reach Jefferson all are wounded and violated physically and emotionally.
- Addie is a complete nihilist who beat her students, had an affair with a minister (can you say Scarlet Letter?), had a child out of wedlock (Jewel), and relished in dying and making her family drag her buried corpse to Jefferson. Getting revenge on your own family after you are dead is completely sadistic.
- Anse is as lazy as the day is long. He is self-serving, caring more about false teeth and a new wife that the plight of his children. He has no idea how to be a parent: his daughter is pregnant; his son is a bastard; his two sons may suffer from mental illness--and he has no idea.
- Cash risks his life to save a coffin (absurd!). He nearly loses his leg after it is set in cement (ouch!). He's obsessed with his things (his tools).
- Jewel is a bastard who hates his family (he won't ride on the wagon with them), but he loves his mother enough to burn his back rescuing her burning coffin. All he does is cuss.
- Darl is either mentally challenged or a clairvoyant genius: he can read Dewey Dell's mind. He is extremely jealous and paranoid of Jewel. He tries to cremate his mother's body (a good thing), but he gets committed to the state hospital as a result.
- Dewey Dell doesn't know how she gets pregnant but wants to abort her baby. She gets raped in the process. She hates Darl because he thinks she'll tell the family she's pregnant.
- Vardaman thinks his mother's a fish. He drills holes in her coffin because he thinks she'll need air. He has no idea what happens to a person after she dies: he thinks his mother will still use her corporal body in the afterlife.
Just to add to the strong points of the above response:
Addie is so perverse in her hatred of Anse that she dislikes all of her children but the "love child" that she has had with the minister, whom she has ironically named Jewel.
Anse is degenerate both in body--hunchbacked with gnarled hands--and soul. In essence, he is sociopathic. He uses his children, forcing Jewel to give him the beloved horse so that he can obtain more mules to pull the death-wagon after the others drown, he scrimps on money, depriving the family of necessities. Even his promise to his dying wife has a self-serving motive behind it: to buy a set of false teeth for himself.
Darl is profoundly jealous of his brother Jewel that he tries to separate Jewel from his mother while she is dying by volunteering him to go with him to obtain lumber for her coffin. So intent is he upon not allowing the coffin to make its destination in order to foil his mother's dying wish that he sets the coffin and the barn it is in on fire. As he is on the train to be committed to an asylum, Darl laughs and talks about himself in third person.
Cash, as already stated, is preoccupied with his tools. But, he is so obsessed that he views his family members as a tool. (How dysfunctional!) He actually names each member of his family with a tool.
Dewey Dell is so ingenuous and crass that she believes that a white powder will cause the abortion she desires. When a pharmist tells her to come back in the evening and he will fix her problem by having intercourse with her as this act will reverse her other act, she believes him. Later, she realizes that she has been tricked. She pushes for Darl to be committed because she fears that he will reveal her pregnancy to the other family members.
Vardamann is the youngest; he does not understand his mother's death. But, on the journey, Vardamann grows closer to his brother Darl and feels the loss as Darl is shipped off to the sanitarium. Because Vardamann struggles to understand Darl's insanity, he becomes more humane than the others of the family other than Jewel, who does truly love his mother.
As also stated by mstultz72, the family is wounded spiritually and physically after this dysfunctional odyssey of theirs. Indeed, this is much in contrast to normal funerals which usually unite members of families.