As a genre “Crazy” is one of the best examples of Vulgar Comedy. It has all the frenzy, the vigor, and the mad ideas it needs, but there is also room for romanticism and historical, social or political references.
It is easy to see how it is sprung from the carnival and the festive rites with its lack of logic and common sense. It is the carnivalistic up-side-down-world where everything is allowed and everyone has a place, a chaotic exception from ordinary life where order is given a rest.
As an example I think HELLZAPOPPIN is one of the best movies ever made in the genre. It was a Broadway show that made it to the movies in 1941, with the two almost forgotten comedians Olsen and Johnson.