To say that "...coffee is perfectly healthy for you" is hardly accurate is it perfectly healthy for people with hypertension or chronic heartburn for instance? BTW I drink coffee daily so it's not like I'm prejudiced here...
http://www.webmd.com/balance/caffeine-myths-and-facts
http://www.mayoclinic.org/medical-edge-newspaper-2010/mar-05b.html
There is always a caveat to everything. Of course people with hypertension shouldn't drink or consume anything that would increase their physiological arousal.
I mean christ's sake, if you drink enough water you can die from overconsumption. Water is pretty healthy for you isn't it?
Diabetics shouldn't consume too many carbohydrates, something that is essential for humans.
My point is that for the average person, there are no health hazards to consuming coffee.
http://www.chess.com/forum/view/off-topic/1000-reasons-why-you-suck-at-chess