It's been a draining evening. Your eyes have long since become glossed over. Dungeon after dungeon -- and every single time, some moron screws it up. "If I see one more [your least favorite class] in these randoms, I'll scream!" you growl as you click "Enter Dungeon" once more. A quick scan through the portraits on the sidebar: "C'mon ... please ..." And then suddenly, a ray of hope. A spark of light (or shadow, or fire, or bullet, or nature, or blade, or whatever) -- maybe this won't be such a bad run after all, since your party now includes a ...
There are 10 potential possibilities for that statement (unless you start making up your own classes, which is silly), but any given response will require clarification. The meat of the question is this: Is there a class that, when you notice one with you in a 5-man, makes you think to yourself, "Phew. Okay. At least we have one of those." Now, what makes this difficult is the fact that there are skilled and unskilled players of every class. One person's relief is another's nightmare. Nonetheless, is there a class that causes you to breathe a sigh of relief when you see its color in your party chat?
For me, it's definitely priests. Something about those flowing robes and that sparkling yellow light fills me with a sense of calm. The sight of healing spells and protective shields radiating all around me makes me feel certain that, despite whatever trials we face, we'll pull through.
Unless it's a shadow priest. No one should be that transparent.