I prefer a cloudy day to a sunny one, and the misty blurred quality that rain gives to the landscape is almost as much of a joy to watch as clouds are when the sun sets.
However, one thing that always depresses me about the rain is that the most beautiful thing you can see during a shower is a puddle of oil, shining in all colors of the rainbow as the first drops of water strike it, and slowly fading to washed-out grays and browns as it makes its way to the gutter, at the beginning of its long journey to pollute the sea.