First we grind the levels. Then we grind the faction. Then we grind the gold. Then we grind the instances for high end loot drops. We also grind out Arena points, crafting levels, bandages for the war (remember those!), potions for the raid, ogres for the Talbulk mount and the daily quests for the flying space ray manta aether thingie from space.
Where does one draw the line? I usually don't run an instance more than 2 or 3 times. Nor do I kill the same thing continuously for faction. I was enjoying daily quests, but they really are just the same thing every day.
A little grind is ok, but too much makes the game not fun and are we not here to be entertained? Where do you draw the line in the grind that is the base mechanic of most MMORPGs out there?