The storyteller of "Family" by Grace Paley utilizes a few descriptors to portray different relatives, and says a portion of the modifiers adhered to her, while others, "discovering me American and smooth disappeared."
This last line recommends that Americans are "smooth," and that modifiers, 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.