I'm running a Dzemael HM from DF. NIN/WAR/BRD and me and WHM. We aren't overgeared and the WAR doe big pulls so outside of needing constant heals I can pull out a Holy to make things easier or a few Stone II. What I didn't realize is that they wanted a heal slave. My mp is visibly low as for whatever reason the Nin AND the BRD are taking dmg (never seen a melee BRD before then) and I popped SoS early before first boss. BRD isn't playing any songs. Ask after the 2nd big pull if BRD can play manasong. I drop dps since it was clear that no one was waiting. BRD refuses to play any song (heck could have played Swiftsong to make rushing faster). WAR pulls boss with me at 700 mp or so NIN starts kills the adds and makes the party eat a chunk of dmg. I'm full heal slave at this point when NIN goes down. I try to rez him.... out of mana. Party wipe.
I again told them that I was OoM and the dps was like "stop dpsing". I asked them if they wanted me to be heal slave and they all said yes. WAR doesn't say anything. Instead of argue, I played the style that people are expecting. The rest of the dungeon goes as planned. Everyone silently doing their job. NIN insults me at the end of the DF. I say nothing.
Not all DFs are like this and I know my job is to heal as a healer role. But good lord if the difference between getting heals plus some dps is a single button press that you don't have to micromanage (manasong or.....any song) why would you refuse to do so? I wasn't rude when asking. I was just shocked at how cold some people are. It's one reason why I stop talking in duties. People are so focused on themselves and are social able to anyone outside their immediate circle of influence.
That said, I just assume (as always) the heal slave role. The argument goes "If you want to dps, play a dps class." I think a better argument goes, "If dps plays their roles better, i.e. stop eating unnecessary damage, any healer can do their role better and contribute to dps to make things go faster.