Agreed, Pliny. White shirts are generally a bit too formal for sports coats, and a bit too refined for the sporty/rustic/rural accessories which go with a more casual code. From first principles: if you're hunting, or inspecting your estate, or attending a polo match, a white shirt will (1) be too bright in direct sunlight, and (2) show the dirt and sweat too easily. OTOH coloured shirts can be disastrous under artificial light as they will reflect "false colours" into the viewer's eyes. Conclusion: white shirts never good for outdoor/sports wear, always good for evening wear. The difficulty is in business attire. Here I think it's up to the individual, but in most cases I would say a white shirt will work with suits, especially if matched with a white PS in a TV fold and a bold tie. But so will a pastel shirt, be it blue, pink or whatever, appropriately matched. In fact I think the plain white shirt is a very versatile choice for office wear.