I have listened to Johnny Cash since I was 6, and his song "One Piece at a Time" is a favorite. It's the humorous narrative of a guy who gradually builds his own car with parts he sneaks out of the automobile plant where he works. But it took 18 years for me to figure out that the words are "I've never considered myself a thief/But GM wouldn't miss just one little piece..." For some reason I'd always thought it was "But gee, they wouldn't miss just one little piece." The accurate rendering is so much better. I'm glad it hit me.
I remember singing " I Will Praise Him" as a young kid in church services, but I could never understand why we were glad that sinners were being put to death. It was a long time before I realized the prepositional phrase in the lyric "Praise the Lamb for sinners slain" was modifying the proper noun (i.e. Jesus), not the verb. Again, accurate interpretation: soooo much better.
The first misunderstanding was a result of faulty hearing, the second of faulty interpretation. Both cases illustrate the importance of a song's words.
"Enunciate, enunciate!" has been the cry of every choir director I've had since grade school. Funny, I never heard that from my band conductors. That's because words carry very specific meaning, and the job of the singer is to communicate that specific meaning to his audience. Yes, instrumental music can (and should) convey "feeling" and bring about an emotional response. But lyrics impart a message that appeals to our emotion and intelligence.
It is worth noting that when God desired to reveal Himself to mankind, He chose to use words--not the music of a song (or a dance or a painting, for that matter). He doesn't want us to just feel something, He wants us to know something.
That Something could be a whole post by itself. Or you can read a pretty good explanation of it here.