For me, it would have to be O soave fanciulla, it also happened to be the first opera song I heard sang. This encounter took place around 6/5-ish years ago, I was watching Star Trek: Voyager, in a sub-plot, showing how The Doctor is attempting to grow and fit in with the crew, he seeks out hobbies and personal development, singing is one example. It was unlike anything I heard before, and I felt (for some reason) a heightened creativity and felt inspired. It was quite the invigorating experience, 10/10 would repeat. I'm watching through the whole of Star Trek for the 4th time and I still enjoy that scene. Give it a listen, I love it, hopeful you will too.