Let me explain..
Rock add pops, I lob it, and bring it behind the pole, usually. Sometimes some tard wants to stun it and try to kill it right there. There's really nothing I can do about that. I can't help them dps, that solves no problem. I can't get it to me because it's stunned and they're silly. I provoke and lob, and it starts to head towards me and dies.
But see, you highlighted the problem with trying to quantify good play. I'm doing my job, i'm picking up the add and bringing it where I want it, a dps screws that up, and even though we're both gladiators (so I'm sure you've run into this), you declare that it's my responsibility to cover their mistake. Suppose that the second spawn of that same add comes in, while big red is up, does his red line attack and gibs the healer. Who does the group auto-blame? Me, even though the problem is because a dps lacks sense.
Again, this is just examples, I realize how trivial the fight is.