Each martial art has its own culture and there are also cultural differences within each school. There is one distinct feature in BJJ which separates it to other martial arts and that is the grading system. Grades within BJJ are slow and cannot be asked for nor can they be predicted when anyone may get one. However, this seems to be acceptable amongst the students which would not work in most other martial arts. The only exception is the Black Belt, which in most systems, shares the same philosophy as any of the BJJ grades.
I believe the difference is because BJJ is a lot more difficult to learn and there are probably more bad days than good days which can knock you back a couple of pegs back each time resulting in no one wanting to rush to the next grade. It's quite the norm students to just sit on the one grade for a very long time with no complaints. Those who have high expectations or make unrealistic demands tend to disappoint themselves and will eventually just give it up. Perseverance is the name in this game. It is not uncommon to see people earning a Black Belt in BJJ after12 years. Ed O’Neil (star of Modern Family or Married with Children) earned his after 14 years training!
Whilst in Karate we do not need to share the same grading system (with the exception of the Black Belt), it is however a great philosophy to think about when we become complacent with Karate gradings. I remember one Master’s famous words in regards to grades, ‘those who ask shall not receive.’