@otakubouzu@Glimmung wasn't there a group of Japanese people that are exactly the same as every other japanese, but due to chinese religion (forget which one) was taken in by japan, those of certain professions were deemed as lesser people. A lot of these lesser peoples ended up joining Yakuza organizations. Though the discrimination of these people has been outlawed by the government, there are still many who face discrimination in many ways. There was a point where major businesses had names and locations of where these people lived as to no make sure to not hire them. If the discrimination has gone down then at least it shouldn't affect that group as much as it once did.
I grew up in a colorful part of Chicago, near south side. Treat everyone with respect no matter who, and you don't have any problems. It helps to know some of the gang members by name. They would help my mom load her groceries into the car.