This in many ways is an odd story. Some of the descriptions, especially of the family, are downright hilarious, whereas obviously the story contains moments of absolute horror when they meet "The Misfit" at the end. Consider the initial description of Bailey's wife:
...a young woman in slacks, whose face was as broad and innocent as a cabbage and was tied around with a green headkerchief that had two points on the top like rabbit's ears.
Clearly this description gives us a good idea of the woman's mental capabilities whilst also being very funny as we are made to compare her with a cabbage and also a rabbit.
However, apart from these moments of humour, I think what is meant to be taken seriously is the way that this family annoy and get at each other. There is something very realistic about the way that the Grandmother tries to manipulate her son to get her way and the fighting between the children. This family, for all of the descriptions, is a family that we can all relate to.