And how rarely does one get the opportunity to thank the authors of these airwave epiphanies?
Well, some years ago (six, if the BBC website is to be believed), Choral Evensong was broadcast from Manchester Cathedral, and the anthem was Haydn's Salve regina. I wouldn't call myself the world's biggest Haydn fan (even if, heretically, I do prefer him to Mozart), but this was a spectacular performance, not least by the soprano soloist, and I made a mental note of the singer's name before filing it wherever it is mental notes get filed.
Then on Wednesday evening I went along to St Magnus Cathedral for a concert by the Marian Consort. Why do I know that name? I wondered; why do I know that voice? Then the penny dropped. One member of that magnificent ensemble was the Haydn soloist: Ruth Provost. It was a really marvellous concert: all Latin texts in honour of the BVM, interleaving Spanish Renaissance settings with contemporary compositions. Often these programmes can end up with a final score along the lines of Renaissance 12 Modernity 0, but in this case, with wonderful works by Andreas Panufnik and Judith Weir inter alia, it came out as a high scoring draw. I'd say it was one of the best concerts I've heard in the Cathedral, comparable with the Cardinall's Musick and Trio Medieval.
And I got a chance to say thank you for one of my radio epiphanies.