I know this is horrible, but I sorta prefer it when our group is without an Enchanter, Shaman, etc. I hate having to sit there watching an add attack the main knowing I could've mezzed it already, or waiting for a shaman to slow at 80% when I could've hit it at 95%.
I have to say, though, my main problem recently has been my old friend, the Druid. Much love to my druid friends out there, but I've partied with some real jerks. The most recent example, the dr00d feels a need to DoT every damned add the second it appears (and includes a nice, mezz breaking AE ice storm every MOB), goes LD every five minutes, and asks for mana song plz every time he comes back (like it's some sort of effect I have to cast specifically on him). Note that mana song has been up for the past hour, even while we were running to our LDON adventure and I stayed near the casters to make sure they were recharged from the buffing.
I did feel gratified when the rest of the group (including a good druid) explained to him that mana song had never been down, but it still strikes a nerve, hehe. I'm not telling him how to do his job.