Red door is a Feng Shui, wanting to paint it black, is a Rolling Stones song, LOL. Black doors and window frames are pretty traditional to me at least. I have always liked black frames (kind of fade into the windows, then surround with a pop of color in trim or shutters, etc).
Grey on houses can be great. There is a house I think is gorgeous I drive by on the way to the credit union. Grey, white trim, green grey shutters. Black houses, not so much. Seen a 1920's bungalow that was painted black, and several others, pink. 1950's weren't good for these, IMHO.