Define a good player

[KaivaC]

Seems the urge to have unusual, but good discussions is strong in me, because I have the urge to throw another one out for the forums. For the last few months, I've been trying to figure out what a good player really is. My own thoughts on it are the ones who have completed Ultimate and God Kefka. For the matter, I do not consider myself a good player, because I have not completed these things or get blue parses (yes, I am aware that I will not achieve that now - but the reference point I was making was before players started getting their BiS and I did not measure up those standards prior to March). So what do you guys personally define as a good player? By your own standards, that is, not one that is drawn up by the community or by the meta.

For a little additional context, just recently, I was just tanking a run and near the end of the dungeon, I lost aggro on one enemy after a pull. Only time I lost aggro at any point in the dungeon (it was a level 70 dungeon), but to me, that's a complete failure on my part as a tank. I've been told I did good as a tank despite that, but my standards as opposed to what others may view seems to differ, so because I lost aggro once, I feel like I was a bad tank. Just for context. I'm not asking for advice or shoulder pats or none of that. I just want to know what you guys think is a good player. It can be overall, or role-specific. I just wanna know.