I think the reason people would want to write is to open up about things. If you can't open up some times it could be hard. Also you could do it on your free time. Also many people write about things that had happen to them. It could be bad or good again you can open up.
I would write about something fantsy. I would write about it because you can make up anything. You could make it funny or sad. Also you could wright about tough times you have in life. I would make my novel funny.