Crazy does happen. We have a crazy day, we are crazy busy. If we are lucky our dinner might be crazy good.
Needless to say, the word is used loosely, at least in the U.S.
The actual definition of crazy is mentally deranged, especially as manifested in a wild or aggressive way. (Oxford) The definition of deranged is (mentally) unsound, wildly odd or eccentric.
I used to believe I was unsound. I still believe I am wildly odd and eccentric.