There are many advantages to pulling a George and Martha book off the shelf when read-aloud time comes, not the least of these being that the stories are incredibly short and can be easily read and enjoyed on those evenings when everyone is too tired for a longer tale. But George and Martha are also great characters. They are quirky and goofy and sometimes a bit grumpy and really, aren't we all? I love the way that their relationship is written in a light-hearted and funny way, while subtly making an important point or two about the ups and downs of any close friendship. These two friends love each other dearly, but that doesn't mean that they always behave themselves or that they don't sometimes need to apologize. I think that it is important for little people to hear that friends sometimes get made at one another or argue over inconsequential things and that they can fix this by admitting their mistakes and being willing to compromise just a bit.
I wouldn't call George and Martha deep metaphorical literature (these stories are, after all, mostly about hippos playing practical jokes on one another) but that is part of the reason why I enjoy these stories so very much. Sometimes a simple, funny story is just the thing to get everyone thinking about ideas that are just a little bit bigger.