I was sitting in a café one day, looking out the window, wondering if different characters would see different things. Maybe a kid brought here by his mom, feeling bored, started imaging a big goldfish was watching him.
Maybe a sales person who had just finished talking with his client, looking out the window, would imagine he had wings like a bird.
What about an old man with the most memories? Maybe in his daydreams, it was love in the past, and regrets when younger.