I really love my job and my students. If there is a better situation for teaching in Japan, I don't know about it.
One of my classes was practicing what to say to show you are interested in what the speaker is saying. "That's interesting", "How nice!", "It is, isn't it?" went fine. When we got to "Oh, really?", the student said it very flat, and I had to laugh when I tried to explain the difference between sounding interested and sounding like you thought the speaker was not telling the truth. The two students understood and I have a feeling that "oh, really" is going to be an ongoing joke.
An upper level class was discussing gestures used in English and comparing them to those used in Japanese. In English, when I talk about myself, I point to my chest. In Japanese, you point to your nose. In English, when I want someone to come to me, I use my arm with palm up. In Japanese, you gesture palm down. One gesture my students had seen on television but didn't understand was the big in-air quote marks. There isn't an equivalent in Japanese. For the rest of the class, everything was in quotes. I was glad the middle finger gesture didn't come up!
I try to make my classes interesting and meaningful and if they can be fun that is an added bonus.