I lived in Japan as a kid - for 4 years. I was pretty young (age 4 to age 8) but if memory serves there were ALWAYS cicadas, every summer. The idea of having them only every 17 years is new to me (we don't have them at all in England, just bloody noisy crickets out in the countryside). I didn't find the sound creepy at all, it was what lulled me to sleep on hot nights.