I actually did have a Mary Sue and attempted several others before. I admit these might be too embarrassing to admit. But I did try at some point or another. I actually think when it comes to what constitutes as a Mary Sue, they’re often intended to be fan proxies. Especially if that author’s a fan of something that they’d do anything to insert themselves in that story.
It makes a lot of sense that most fanfiction Mary Sues are fans’ wishes to either be part of that world or be that character. It’s even more blatant with canonical characters intended as audience surrogates where I think they have a better chance of being considered Mary Sue really. I think these are the easiest to live vicariously through although any character would do.
I think when it comes to Mary Sues, the more an author likes the character or identifies with them the more they idealise them a lot. Same if they like franchises as a whole that in order to not make a Mary Sue authors can like the character but still either allow them to do whatever they need to do or to base them after somebody else. Albeit in a non-idealised manner (this goes if said character’s based on themselves).
That’s on top of having an actual personality, which I think most Mary Sues don’t.
fynm 