Kinda stupid question, but was wondering. I washed my car and my roommates car on the same day. I took my time with mine, and when I finished with mine it was like just waxed look. (Water and car soap) I washed the roommate's car right after that, didnt take the time with it. Got it wet, soaped it, rinsed it and quickly dried it out. It rained this morning any my paint/glass (black) is all filthy again, water spots. The roommates doesn't show it, but then again it's a green car. Thoughts or I am crazy or is it just because its black and makes them standout?