I do have to disagree with you. "busywork" makes it look like you're doing work. Often you can get away with it. You might very well be doing work but you're not really doing anything of value.
World of Warcraft can feel like work but you're not really trying to pass it off as work. If you managed to do that, who ever you work for certainly has some issues!
The grinding kil-15-wolfs type of missions often had me going: "ok, only 3 left.. phew"