I agree it's his humour combined with an economic style. A real joie de vivre shines through much of his work. I have his book Personal Exposures and his introduction to that book is very much like his photography. Clear, economic and often humourous and insightful. I rarely laugh out loud when viewing a photograph but have done it many times looking at his work.
This thread also gives me a chance to show off my picture with Elliott taken in Sydney a few years ago at the opening of an exhibition of Graham McCarter's photos. I recall he was in Sydney to speak at a convention and was aware of Graham's work and decided to come along to this small gallery and mingle with the opening crowd. Quite a shy man in person but always a twinkle in the eye!