Once you realize that even slight tardiness can be considered as a huge offense, you'll start to understand why so many j.a.panese gang members have missing finger joints.

In j.a.pan, only gang members have tattoos. Normally it can also be considered a basic requirement. Also those aren't traditional tattoos made using a machine. Those are carved into the skin using a stick over a period of several months or even years.

Once you enter that kind of lifestyle, you'll be marked for life. Although tattoos can theoretically be removed, fingers can't regrow. Also the tattoo removal would definitely cost a lot and be quite painful.