The storyteller of "Family" by Grace Paley utilizes a few descriptive words to depict different relatives, and says a portion of the descriptors adhered to her, while others, "discovering me American and smooth disappeared."
This last line proposes that Americans are "smooth," and that descriptive words, or thoughts regarding individuals, can "slip" off them. This appears to imply that Americans are not ready to see past the self-evident; don't look further into a thought.