I think if you live in any country long enough , you will run into someone who is trouble. Although it was rare in Japan , once in a while a very drunk man would get loud. In my two years , the only one I really remember was a drunk yakuza with a knife was very angry my 5 Japanese female friends were with a gaijin. Lucky for me , when I approached him , he ran away. This was during the early 70's and I considered Japan the safest place I'd ever been.