Unfortunately I often fall into the trap of only giving commendations to healers when the party takes lots of damage and the healer manages to keep us alive and raise quickly. In some cases that is very much justified but in other cases the reason the party gets so low on health might be that the healer isn't paying attention in the first place. In a perfectly smooth run, right or wrong, I tend to give commendation to my fellow DD if the mobs are going down quicker than normal or the tank if they are going down as normal or slower but I never manage to pull hate. It might not be fair to the healer but sine I am focused on my job those are things that I notice and they therefore influence my commendations.