Funny you should mention lyric memory. In 40 yrs of pickin, I've NEVER been able to remember the words to songs, always use a music stand on stage, sometimes just as a crutch, just knowing they're close by. I attribute this to lack of interest to the lyrics as I'm really more interested in the instrumental aspect and harmony arr. than what's being said.
Good example of how tenuous our grasp of originality can become.