When I was younger, and I was in the car in the rain, I would watch the rain run down the glass, picking different drops and watching to see which one ended up being the ""winner."" I don't know what the winner achieved, other than being the first to drip down into the base of the window, but it gave me a thrill of the anticipation of which would reach the bottom first. Even now there are times where I find myself watching the rain, feeling a sense of nostalgia as the rain patters down.
I always felt so vindicated when I chose the right raindrop, feeling as though I, myself, was the victor. I feel as though it's only natural to see yourself in things, even to the point where you feel as though there's a part of yourself in every little thing you see. You want to see yourself in the world and in others, you want to not be alone, even if it means putting yourself out there and putting yourself in others.
The rain is a natural starting point, who hasn't had a moment of watching as the trails down the glass.