Often songs - like poetry - often aren't insightful exactly, but provide a good way of communicating the emotions connected with an experience or concept.

Take Smells like Teen Spirit" (which appears on 6 of the lists linked to above): The lyrics are not particularly insightful (almost deliberately), but it captures the goalessness of disaffected youth like no other song.

Nothing Compares 2U* really is unrequited love.

Then there's U2's One (3 lists) which has lyrics that mean different things to different people, and music that can support multiple interpretations[1].

(Of course, some songs on those lists are just entertaining because they are perfect pop ("Billy Jean", "Like a Virgin") or funny ("Baby got Back")

[1] http://www.pophistorydig.com/?tag=u2-one-song-history