We clear the first couple pulls and reach the main part of the instance, where the tank begins pulling (yes, pulling, not just charging in and pulling 20 mobs because of patrols) mobs. Next thing I know the ret paladin is out in the middle pulling mobs. After a very harrowing and frustrating 5 minutes, we manage to pull through and kill all the mobs with no deaths.
I ask the paladin to let the tank pull and leave it at that. Couple pulls later he's about 20 yards away pulling a banshee; I decide to not heal him and he dies. I explain I don't heal dps who pull for the tank; and the ret paladin tells me to shut up and do my job, though not with such nice language. I tell him my job is to heal the tank and heal dps hit by unavoidable damage and that I won't be healing him the rest of the run.
He spends the next 10 minutes berating me for my unwillingness to heal him. Finally he upset the group enough they kicked him. Rest of the run went fine and dandy with only one small hiccup.
Why do some dps feel it's okay to make the tanks and healers play time less fun?
When a group cooperates and works well together, everyone has fun and the instance goes well.