"Pleasant Valley Sunday"

Last Sunday, I was thinking about "Pleasant Valley Sunday," and I realized that the lines "Mothers complain about how hard life is / And the kids just don't understand" contain a grammatical ambiguity.  I'd always thought these two lines were linkt and that the mothers complained about two things: 1) how hard life is and 2) that the kids don't understand.  On Sunday, I realized that these could be two distinct statements: the mothers complain only about how hard life is, and - as a separate comment - the kids don't understand.