A song you've seen performed live, or would really like to see performed live?

One of my most "holy shit I can't believe I'm watching this in real life" moments was at the Middle East in Boston, I can't remember how long ago, watching this Japanese band Envy that I had been trying and failing to explain to all my friends how rad they were. They're a great band all around, but this song in particular gives me goosebumps every single time. It just goes on such a journey. Soft, pretty, delicate, to loud, chaotic, crazy time shifts, back to mellow, back to frantic insanity, and then about 3/4s of the way through drops into this amazing straightforward rock screamo finish. It might be the perfect song, in my opinion.