I read an essay years ago describing "If", "Invictus", and "Trees" (by Joyce Kilmer) as the three worst poems in the English language. I can't find the essay, so maybe I have the three poems wrong, but once you read them side by side, you definitely get a sense of the different kinds of nausea literature is capable of generating.

But the common feeling is greeting card sentiment poured forth with the stridency of a real professional.