I can’t remember a time I felt so profoundly disquieted by a Handel staging. It’s partly that, as an oratorio, Saul breaks so many dramatic rules that lend the operas their reassuring structural certainty, but there’s also something – a tenderness certainly, but also a violence – to Barrie Kosky’s production that uncouples the music from any residual cosiness England’s favourite adopted composer still inspires in British audiences.

Britten’s first chamber opera is very much a Glyndebourne piece; its world premiere in the old festival theatre in July 1946 was also the festival’s inaugural post-war production. It brought into being the English Opera Group, and led soon afterwards to the foundation of the Aldeburgh Festival. So it’s good, in principle at least, to have it back on the main stage here, after an initial airing on tour in 2013. I say in principle, because in practice the work and its staging present so many problems that I can’t ever recall seeing a production without wincing with irritation.

What a difference seven years can make to a budding genius. Mozart’s La finta giardiniera (1775) has only patches of brilliance, and last year’s Glyndebourne production, despite musical excellence, failed them all.

After Calixto Bieito’s radical reimaging of Carmen, which opened at English National Opera this week, David McVicar’s version at Glyndebourne was bound to seem conservative. But it turned out to be a comparison of apples and Seville oranges: Bieito is certainly bolder, but McVicar is more sophisticated and digs deeper into the raw emotions of the work. It’s not a new production, but revival director Marie Lambert has kept it fresh, aided by a stunning cast and dynamic, energised conducting from Jakub Hrůša.

Fashion is a funny thing, in opera no less than the sartorial trappings that go with it (everything from tight, hipster trews to billowing ballgowns at last night's Glyndebourne season opening, in case you were wondering). Donizetti's classical tragedy Poliuto is historically a miss rather than a hit, never quite finding its footing in the repertoire, despite some early success.

When everything works – conducting, singing, production, costumes, sets, lighting, choreography where relevant – then there’s nothing like the art of opera. But how often does that happen? In my experience, very seldom, but not this year. It's been of such a vintage that I couldn’t possibly choose the best out of six fully-staged productions – three of them from our only native director of genius, Richard Jones, who as one of his favourite singers, Susan Bullock, put it to me, deserves every gong going – and one concert performance.

Usually, anyone bringing tuberculosis and transgression to the regional centres of Woking, Norwich and Milton Keynes would meet redoubtable opposition. In the case of Glyndebourne’s new touring production of La traviata, that would be a shame, because this is a lean, powerful version that reaches straight for the heart and gives it a good squeeze.

God it’s good to laugh in an opera house. Not a hear-how-clever-I-am-to-get-the-laborious-operatic-joke laugh, or an I-realise-this-is-supposed-to-be-funny-so-I’m-playing-along one, but a real, spontaneous laugh that tickles into sound before you’ve even had time to register its approach. Back for its second appearance, Robert Carsen’s Glyndebourne Rinaldo is ingenious and witty, joyous and completely over-the-top, and the best possible ending to this year’s summer opera season.

If you only ever listened to opera from recordings, you might overlook the fact that it's as much theatre as it is music. In the opera house on the night, it's all well and good for the orchestra to play the score and the singers to sing their parts, but on top of that you have to allow for costume changes, move the scenery, adjust the lighting and make sure you get all the right people on and off stage at the appropriate moments. It's what makes opera the living, breathing, sometimes splendidly chaotic spectacle it is.

Some of us have witnessed Traviatas where single stars were born: Angela Gheorghiu for Solti at the Royal Opera nearly 20 years ago springs quickest to mind. Some would claim a dream couple in Anna Netrebko and Rolando Villazon on peak form at Salzburg. Yet how often in a lifetime do you catch an evening like this, where all three principals are not only up to the very highest vocal standards but also work as one with the conductor to make sense of every phrase, every word, in an intimate space for which Verdi's chamber opera might have been crafted?