Watercolor: a medium for the curious, the impatient, the impetuous. For me the best part is wondering: how will the paint finally settle? My intention is not to depict objects or places but rather to emphasize some bits and neglect others. Contrast and balance are most important, details not so much. Imagination can do amazing things, and I want the viewer to wander around the picture with their own musings.
Usually my color palette is rather limited involving blues, greens, grays, and browns. It is not that I prefer these colors, but that they play well together and can set a thoughtful mood. Occasionally a red will creep in, but that can be such a strong and dominant feature (I use it sparingly).
Finally, granulation is something I highly prize, and you simply cannot get such an effect in any other medium. Fortunately this behavior matches my impressionistic, loose style. While I frequently start with an idea for a painting, the interesting ones evolve into something essentially unexpected. Perhaps my experiences as a mathematician have led me to appreciate the randomness of life. I am now an addict of the watercolor surprise.