Black belt in crazy

Nick, a friend from new york, has sent me a cool t-shirt yesterday. It has printed on it: "I got a Black Belt in Crazy".

This cause a little email exchange:

Hi Nick!
I just got your Tshirt. Thanks a lot! Nice present!
However, I do not fully understand the Print on the Tshirt.
(my awezome Gzerman Engliz Zkillz)
Shouldn't it rather read:
"I got a black belt in craziness"
than
"i got a black belt in crazy)?


His answer:

!! You astound me with your perception of English grammar. I think we
Americans would be like, "oh, okay".

But the real question is: what would a true "black belt in crazy" prefer?

But it's legit! At least in popular culture with songs like "Halfway
to Crazy". OK, rock musicians might not have the best English either.
Maybe it's a bit poetic(?).

My theory: English is a bit like a PC C++ compiler from the 90's! If
it compiles on at least *one* compiler, it is a "valid enough" feature
and okay!


Well, with the C++ analogy, it kind of makes sense to me now :-)