Healing is easy, you don't need to do much usually other than keep idiots alive and manage your mana. In recent raids they've given you stuff to do, like healing the good water elementals/spirits in the Immerseus and Gorefiend fights. Healing bar blindness is something though, couple of times I'm surprised to note the fight ended so that was why no one was taking damage.
PvP healing is a f'ing pain though, addons mean you get primaried easily and good luck on some PUG helping you out. Still, I can take a bit of punishment and sometimes opposition are pretty stupid and don't hit the healer. Does get annoying when some warrior expects me to babysit his inept ass as he just runs around, his resultant death and bitching does please me somewhat.