Believe me, I've spent years thinking about this.

When I was in eighth grade I wrote a Mary Sue. This is especially interesting considering I was in the PPC at the time and I had recently gotten Permission. My Mary Sue, however, wasn't a self-insert; it was a glorified version of a friend of mine (I eventually revised the hell out of her and turned her into Lori Starrett).

A Mary Sue appears when a writer is blind to their(or the person they're trying to write in's) flaws. At the time I did not see that [Lori] was a naive and rather mildly racist person who, despite our converging of interests in social politics, is still going to vote for Mitt Romney (I'm trying my best to be neutral here but I really don't like that guy), so I put her on a pedestal and subsequently her character became a Mary Sue.

Suethors who write self-inserts, on the other hand, often try to dissociate themselves from their creations (because if they acknowledged it was a self-insert, they'd have to look for their own flaws in that character and Mary Sue is Too Preshus To Have Flaws). However, they can't help but insert the positive aspects of their personality, and try to come up with milder flaws in an attempt to balance things out - but of course, that never works out because the canons love her flaws, too.

Character writing for the average teenager is ridiculous amounts of hard. I wasn't even technically teenaged when I got Permission, so I'm one of those freaky kids who started writing at the tender age of ten and therefore nipped most of it in the bud, but I can tell you a person at that age is 1) still struggling to understand themselves, 2) not experienced with creative writing, and 3) not experienced enough to make believable things happen to their characters. It's much easier to make a Sue when you're younger, trust me.

It's even easier to make a Sue on your first go at character creation, no matter what your age is. Generally the first character of many writers is the result of years of inexperience in character creation, so the majority of First-Fanfic OCs tend to be Suvian.

Conclusion: Suethors are always going to exist because we can't expect children, preeteens, and most teens to understand life enough to create living characters. Personally I just wish they'd keep the fics to themselves. Sue/Canon is one of the most selfish things a writer can do, because it's telling the world to PAY ATTENSHUN TOO MAI OC U GAIZ, SHES PERFECKT AND IF U DONT LIEK U WILL BE ASSIMILAYTED!11!1ONE! at the cost of everything else.

-tries to take off fangirl psychologist glasses-

Here, come and sit by the fire. We shall shoosh and papp each other on the heads, read goodfic, and rejoice over the knowledge we share. Then, after being revived through the power of chocolate and bleeprin, we can examine those... things.

/papps/ It will all be okay.