Like the modern romance novel or murder mystery, late-eighteenth-century opera buffa is a thoroughly conventional genre. Standard plot devices, stock characters and vocal types, and particular kinds of musical number appear again and again, and any reasonably comprehensive understanding of the genre requires that we recognise these familiar patterns in text and music. This is especially important in the case of Mozart, who lies at the heart of our interest in the repertory: while his operas are routinely praised for their uniqueness and originality, we can evaluate these claims only by addressing the formal and stylistic procedures that served as his immediate context.

Heinrich Dorn, conductor, composer and critic in mid-nineteenth-century Germany, was well known to his contemporaries as a man who disliked Wagner's music. He himself always claimed to have given Wagner every chance: ‘Sensible people who do not set themselves blindly either for or against Wagner's music’, he would comment, ‘cannot but admit that he is the greatest of living composers’. Yet his reviews of Wagner's work invariably ended in querulous diatribes against what he considered Wagner's refusal to supply the necessities of good operatic composition – lively plot, singable melody and if not traditional then at least recognisable forms – in works that, moreover, were far too long. ‘Individual moments seize one’, Dorn wrote after attending dress rehearsals for the Munich première of Tristan and Isolde, ‘but they are, as so often in Wagner's music, oases in a vast desert. … The second act of Tristan seemed to drag on even more endlessly than the first, and at last I found myself in such an apathetic condition that I almost turned and bit my neighbour … just to be delivered from the prevailing circumstances’.

In Herman Melville's story, Billy Budd, Sailor (An Inside Narrative), the potentially mutinous reaction of the Bellipotent's crew to Billy's execution is quelled by a call to order:

For suddenly the drum beat to quarters, which familiar sound happening at least twice every day, had upon the present occasion a signal peremptoriness in it. True martial discipline long continued superinduces in average man a sort of impulse whose operation at the official word of command much resembles in its promptitude the effect of an instinct.

Imagine what would have happened if Prospero had come out in front of the curtain at the end of the first performance of Shakespeare's Tempest on 1 November 1611 and if, at his words

Now, 'tis true,

I must be here confin'd by you,

Or sent to Naples. Let me not,

Since I have my dukedom got

And pardon'd the deceiver, dwell

In this bare island by your spell;

But release me from my bands

With the help of your good hands.

Gentle breath of yours my sails

Must fill, or else my project fails,

Which was to please […],

the audience had not applauded. In accordance with Jacobean theatrical practice, the sound of applause breaks the theatrical illusion.