Work was slow the other day. I had some downtime but didn't use it wisely. Instead I was starring around the teacher's room. Feeling like I had nothing better to do, I started to whistle. After about a second of that, my Japanese English teacher said something really funny. 'Don't do that, you will call snakes here'. She laughed, then told me that whistling indoors is considered rude. It's nice when the Japanese get straight to the point with cultural stuff. Usually they take the long way and you won't find out you've done something wrong until weeks later.