Well, it's certainly the key to a successful show. The Simpsons, for instance, has several different levels of humour often within the same joke, that means it appeals to adults and youngsters equally. :-)
There's a similar dynamic in the surrealism of shows such as Button Moon, The Magic Roundabout and even Sooty, that I feel is painfully absent from anything I've seen produced recently. One possible exception being the Teletubbies, although I haven't watched that enough for it to annoy me yet. :-D
