I would say the most striking criticisms Irving levels at human beings (and general human society) can be found in the characterization of Tom Walker, along with his wife, whose extreme parsimony and pettiness was such that they made themselves miserable. This extreme, self-defeating miserliness is reflected in the condition in which the two live. They have taken miserliness to the highest point of absurdity, to such a degree that they have become impoverished for it. Consider, in the beginning of the story, the description of the house they live in: "they lived in a forlorn-looking house that stood alone, and had an air of starvation." Later, after Tom sells his soul to the devil, this same absurdity would continue to manifest, as now he would reside in a vast mansion (largely incomplete) and riding around in a carriage, pulled by starved horses. There's a tension here, between the ostentatious desire for status and prestige, continually undermined and made pointless by his own stinginess.