I mainly read mythology as a backround to a field that I find more interesting, linguistics. I have a fairly good knowledge of Slavic mythology, less so for Norse and Greek mythology, and Celtic, Egyptian and Indian I only have some general ideas about. I like reading them to get a window into the life of people of ancient times. Studying languages bears even better fruit in this regard (in my humble opinion). I had been learning Old Norse for example, and enjoyed learning Latin in high school.
I also read "Antigona" and "Prometheus in Shackles" in high school. If I had more time, I would study some myths more thoroughly.