As a satirist, Sinclair Lewis plays the part of the chameleon really well. Whenever he's writing about a particular kind of character, he'll actually transform the tone of his writing to exaggerate that character's personal shortcomings.
With Angus Duer, for example, Lewis writes,
Angus Duer's studiousness and his reverence for correct manners were alike offended by Clif's bawdy singing, Clif's howling conversation, Clif's fondness for dropping things in people's soup, and Clif's melancholy inability to keep his hands washed. (3.7.1)
In this passage, Duer's prim view of the world is reflected in the ridiculously proper tone that Lewis uses to write about him. Words like "studiousness and reverence" indeed do a good job of describing Duer, but the snob-tastic tone of these words do an even better job of telling us how hard it would be to hang out with this guy for very long. Clif sounds like a jerk-o, but we'd feel more sympathetic towards Duer if he "hated Clif's dirty songs" rather than being "offended by Clif's bawdy singing," or if he didn't like "Clif's gross hands" rather than "Clif's melancholy inability to keep his hands washed."
"Meloncholy inability to keep his hands washed," especially sounds super priggish and stuck-up, right? How are we supposed to feel bad for Duer? Oh wait… we're not supposed to. We're supposed to think he's a snootypants.