I used to think clouds were flat and pressed against the sky. I thought this right up until I was 12. Twelve.
You see, despite living in Chicago and riding on trains leveled over 50 feet in the air for all of my childhood, I had never actually seen a floating cloud due to all the large buildings throughout the city. Not to mention it rained. A lot. Still does. Thus, I always saw the clouds from my short little perspective, and from there, it looked as though the clouds were right up against the sky.
I didn't see my first actual floating cloud until I was in Atlanta, which has a few elevated train stations. However, they have very few tall buildings, so when I looked out the window, I saw a cloud floating out in the distance. I was shook. I had never seen that before, and so I raced to the library as quickly as I could to learn more about clouds and precipitation, and while I knew it was made of water in a gaseous state and all that jazz, I did not know there was a crapload of distance between clouds and the barrier of the Earth's troposphere. Now, I am far more aware of clouds and whatnot, especially given I've traveled a lot more. Clouds are honestly pretty neat.