Things you should never do in Japan

After living in Japan for almost 20 years, I've made every mistake that can be made. Japanese culture is fascinating and very deep. There is always something new to learn. I hope to share some of the things I've learned so you don't make the same mistakes when you travel to Japan.
Try to learn as much etiquette before you visit Japan, but don't worry about getting everything right. People are very forgiving as long as you are respectful and show that you are trying. If all else fails, just watch what other people are doing and copy them.