There's something about song that is different than regular speech. It's easy to remember the lyrics to songs only having heard them a few times. Placing a rhythm and melody behind words somehow gives them force that transcends words that hang in the air with no tonal support. They tug at our emotions and bring us more fully into the full sense of the words that come out of our mouth. Most often, even if we can't meet the correct tones ourselves, we are struck by their depth of meaning.
The hymn writers, I think, had a strong sense to this. Edward Mote, desiring to write a hymn that explained the gracious experience of a Christian wrote "Solid Rock." We sang this at Grace a few weeks ago. The fourth verse struck me hard,
When He shall come with trumpet sound,
Oh may I then in Him be found.
Dressed in His righteousness alone,
Faultless to stand before the throne.
What lyrics, Christ-exalting or otherwise, get stuck in your head? Does it cause you pause when you get out of the car and Akon is the only thing banging around in there? It does me.