I found this image online.
I like to say ‘A black belt is simply an expert at the basics.’
I am always somewhat annoyed (offended?) when I see people wearing their belts in public. It does not matter if the belt is yellow or black, you are not impressing anyone that matters. In fact, you are just drawing unneeded attention to yourself.
If you are training in ‘martial arts’ because you want to be cool or impress people, then you are unlikely stick around long enough to get a real brown belt* – not to mention a black one.
* If you have signed a multi-year contract to train then you should seriously ask yourself if you really earned your belt, or if you just bought one.