It's really a matter of scale, though. A first verse is going to be rhymed, at least, and it's going to have something to do with the chorus, which repeats. An opening song on an album, likewise, is like 10% of the content. By this point I've already typed four sentences and we're a long, long way from being a novel or a story. Know much about ragas? So there are three notes there (which are optional) followed by a strum. That strum does define pretty much half the raga - it's the key the piece is going to be in. An opening sentence, though, does nothing more than give you a taste of what you're about to hear. It's like one note on a piano which is enough to let you know you're likely going to hear some piano in whatever comes next. The "rug" comment is better. It's like looking at a thread from a tassel and saying "I think the rug is likely to be red."
There is no doubt that judging a book by its first line is even more ridiculous than judging it by its cover. Since this is about having fun and challenging oneself creatively, it may be a more interesting exercise to say, "tell a story in less than 5 lines."Know much about ragas?
Yes, actually I do know a bit. A friend of mine is a tabla player and I've heard him play (with others) many ragas. -Sort of a "theme" within a formula.