I've saved some groups from so many wipes just because of Clemency. Healers shouldn't be butthurt about a heal going off every now and then just like how dps don't get mad when healers dps some. Sometimes, healers tunnel vision (I know I'm guilty of it at least a few times) and a quick clemency on yourself or a party member makes them go "oh, whoops!" I really wish people wouldn't take these things as a slight against them or their capabilities. Sometimes a tank just gets nervous. Especially with all the bad healers I've had.