I commend the person who was the most influential in making the dungeon clear go fast. I don't limit myself to commending any person based on role. Sometimes it's a healer that not only keeps a tank alive, but adds considerable dps to killing trash. Sometimes it's a tank that pulls cleanly and with gusto, uses cooldowns, and makes life easier for healers and dps alike to maximize party jobs effectively. I'll even com dps who go above and beyond just looking to take care of themselves; this means using those role actions effectively to bring a swift conclusion to a dungeon. In short, I com people that deserve to be.