I'm singing in the rain, I'm singing in the rain...
Have you ever watched raindrops run down a window? Not just seen them, or followed them, but really watched them. They make such beautiful patterns, running into each other and combining until you get a really big raindrop. And if you're lucky, it makes a pattern. Sometimes you'll get one of those super-drops and it'll run down the glass until it hits a smaller one, and split. Then the two new drops will go in two different directions and slide down a little bit and maybe even meet up again - and then you can see a heart. And you'd never have noticed it if you weren't watching.
But sometimes you wish you could do more than watch. You want to be that raindrop, joining and splitting and then finally joining again. You want to be one half of that heart, but you can't do that, because the other raindrop has suddenly seemed to evaporate.
Then again, what goes up must come down. Eventually it'll rain again, and you'll be reunited.