If you were a brilliant lawyer strongly committed to your craft, you would not get tattoos or dye your hair purple. The reason is simple: too many people would see it and think less of you. As such, it makes you less able to effectively defend your clients. When your job involves appealing to society on behalf of someone, you do not make a middle finger to that same society an immutable part of your appearance unless you are very thoughtless, also not a characteristic I want in a attorney.

There's also the fact that law, more than most disciplines, is premised on adherence to old, old forms of tradition and ritual. In britain they still wear powdered wigs, for goodness' sake. The law still uses Latin terms though it's decades to centuries since educated men learned it in school. Our legal tradition in America is old, with Common Law in some ways tracing back to William the Conqueror. The other major legal tradition on which I've read, Justinian's Codex and its evolution into the Napoleonic Code, dates back to the 500s AD. Discarding old customs, even if you think them outmoded, trampling social niceties because you find them outmoded, is a really bad sign for a capable attorney.