"In the United States, there one feels free... Except from the Americans - but every pearl has its oyster"

This quote by Randall Jarrell is a humorous take on the idea of liberty in the United States. He recommends that in the United States, one can do not hesitate from the restraints of culture, however not from the Americans themselves. This is a funny means of stating that the American individuals can be fairly opinionated and judgmental, and that it can be difficult to escape their examination. Jarrell is implying that the American people can be like an oyster, shielding their pearl of viewpoint and judgment. He is recommending that although one might feel free in the United States, it is not always easy to escape the judgment of the American individuals.