There is a fault common to all singers. When they're among friends and are asked to sing they don't want to, and when they're not asked to sing they never stop.
How charming is divine philosophy! Not harsh and crabbed, as dull fools suppose, But musical as is Apollo's lute, And a perpetual feast of nectar'd sweets Where no crude surfeit reigns
And this shall be for music when no one else is near,
The fine song for singing, the rare song to hear!
That only I remember, that only you admire,
Of the broad road that stretches and the roadside fire.
You would never hear any song played twice in the same way. The words were retained, but within a certain frame there was great latitude, and the musician could improvise to his heart's content; and the more the variations and combinations, the greater the musician.