I think that, as a child, this book would have terrified me, but my kids seem to love it! Perhaps because they know what wonderfully well-mannered children they are...
It's a cautionary tale, in the mould of Hillaire Belloc, but much more sparing with the words. Billy is a very spoilt child who is shown a series of wonderful things, such as the world's curliest trumpet, and the steamiest train. Billy's only response to all of these things is "whatever". In the end Billy's Dad shows him the world's hungriest tiger. After the tiger eats him, he shouts to his Dad that he is still there in the tiger. Dad's reponse as he walks away? "Whatever".
This book is wonderfully illustrated - they are bright and simple pictures, which remind me a little of the iconic Mr Benn.