Rezzing is fun after the fact, but I really enjoy the last minute saves you can only get as a healer. There's nothing like coming across a player who's pulled an add too many and is just fighting to get the xp from 1 of the mobs. You can see the desperation, but then you swoop in with your heals and your buffs...

Open world aside though, I like being the life-line of the party and the first target everyone rushes to defend if they get attacked.