I'm a twentysomething law student who wishes she was writing professionally. My first fic was a Mary Sue. Ditto my second fic. By the time I graduated from high school I'd pretty much purged Mary Sue from my psyche, but every now and again she creeps up on me. I did do my undergraduate degree in English, but I focused on Grammar, and freelance editing is paying my bills. So I'll catch your Tennyson ripoff but I'm more likely to be annoyed by your misuse of the contraction "it's".

I feel intense pity for people who have not yet heard about Mary Sue. I personally think she's an expression of teenage girls' latent need to be recognised in literature. While the Harry Potter saga has got Hermione and McGonagall as very strong female characters, they are far outweighed and outshone by the male cast. And the Lord of the Rings only has Galadriel and Eowyn alongside dozens of male roles. Girls who write themselves into popular fiction are, in my opinion, expressing their need to have a place in the great spiritus mundi of literature.

However.

Sleeping with the entire male cast - Legolas and Draco especially - is a sad reflection of what girls see as a measure of self worth. It's the pushup bra of fan fiction. If you're going to write a Mary Sue, make her smart and funny without prattling on and on about her "gleaming raven hair" or "sapphire eyes" or "curves in all the right places". I mean, have some self respect.