For me mostly it's brain creep. I'm constantly amazed when I give someone else the words to a song I do (and it's the same set I learned from) that I no longer sing it exactly the same way. The synapses synapsed and this was the result. It's "mostly harmless." It's unintentional and the meaning of the song hasn't changed.

Occasionally it's necessary to change a referance or wording to avoid a wrong interpretation or term that is no longer acceptable to politically correct ears, but the change is minor. I've also tweaked content to change the gender of the singer, but not often as it usually isn't appropriate or necessary. I sing plenty of songs from a male point of view.

Linn