Was it Frost or Sandburg who said something like writing free poetry was like playing tennis without a net?

I too prefer rhyme in song, especially with the addition of internal rhyme, which adds such a rich texture, partly because it means that a lot of thought and attention went into it, and it isn't really that difficult, besides. It continually amazes me that the English language lends and bends itself so readily to emotion.

That said, there are a number of songs that I enjoy that don't have even rhyming vowels.