Death (famous person recently deceased of old age)
The recently deceased Brian Wilson wrote God Only Knows, a Beach Boys song that Hans Zimmer has described as "a perfect song", and Paul McCartney as "the greatest song ever written." (Even if you assume I don't know shit about music, those two certainly know their shit about music.)
You know what that song doesn't have? A key. Nobody — not even Brian Wilson — can or could tell whether it was in E or in A major.
