There is one thing far more frustrating than having to wait extra time for testing. Some martial arts instructors award rank far too easily and far too quickly. In the short term, the rank advancement feels good; in the long term, when one feels that one's rank is higher than one's skill, one can lose trust in their instructor and their school.
One of the first martial arts I studied quickly awarded me a brown belt that I had not earned, and I dropped out soon after. Another martial art that I studied was about to award me a brown belt that I had not earned, but I dropped out before they could do so. I do not see this pattern repeating itself with my aikido training. In aikido, I appreciate the fact that I will have to work hard for a long time before I can earn a brown belt. I appreciate the fact that my sensei sometimes tells me that I'm not ready for testing instead of being overly eager to collect the testing fees. I deeply appreciate the fact that my sensei offers honest feedback on areas that I need to work on instead of giving me vague platitudes of praise.