I try to finish my showers with some cold water to get the circulation going, but I'm not sure I'm at the level where I would be able to take full showers that are just cold.
Of course, when there have been problems with the hot water, I've had cold showers, but it's not something I think I want to choose on regular basis.
btw, I never really take hot showers, I tend to use water that's between cool and warm, but firmly on the warm side (if that strange explanation makes any sense at all).