What if there is no gravity

When I was a teenage student in junior high, our natural science class teacher, a young woman, once gave everyone an assignment: write a fiction about "What if there is no friction".
Holding a lot of teenager rage by then, I felt that stupid assignment was an insult to my intelligence. So I decided to give my teacher a lesson that she won't forget for a while. My "brilliant" fiction story began in a very nice ordinary sunshine day, and then slowly turned dark into a catastrophe with alien invasion. In the end of that story, I left a vivid description of how everyone's eyeballs were popping out of their eyes and flesh were slipping down from their body, as the result of zero-friction field created by the alien. I must have scared crap out of my teacher, because she not only gave me a "C-" plus a critique, but also went on criticising my horrific fiction in the following class and praised a moron who wrote something like people don't need cars since they can slip from one place to another...
That was decades ago, and I am an different man now. If I have chance to talk to that rebellious young me, I would tell him that I shouldn't write that - not because my fiction story wasn't good but because it was easy. I should challenge myself instead, use my young creative mind to write something new, beautiful and mind-blowing. From time to time, when I watched a Sci-Fi movie which ended up as a thriller, it always reminds me about that young boy sitting in the classroom, staring at the "C-" that he got.