You're such a Mary Sue that Rapunzel asks you for hair-care tips.

You're such a Mary Sue that Doctor Doolitle is jealous of all your cute animal friends.

You're such a Mary Sue that Imelda Marcos borrowed shoes from you.

You're such a Mary Sue that men are queuing up to be your Designated Misogynist Bastard.

You're such a Mary Sue that people are scuba diving in the deep limpid pools of your eyes.

You're such a Mary Sue, unicorns want you for Christmas.
You're such a Mary Sue, Wolverine and Batman think your past is too tortured.
You're such a Mary Sue, scientists have tried to replicate your smile to use as the first nonrenewable light source.
You're such a Mary Sue, Excalibur thought King Arthur was you.
You're such a Mary Sue, the poor, hungry, and sick worry about you.

Yeah, these get kind of convoluted as they go on.

"Your mother was a Mary Sue, and your father smelt of body spray!" (A classic. Use on OCs, with caution.)

"When the Bard said 'Tis too much proved that with devotion's visage/And pious action we do sugar o'er/The devil himself', he probably had you in mind." (Or 'one may smile and smile, and be a villain.')

"You're such a Mary Sue that Bella Swan hates your guts!" (Followed without fail by choruses of "Ohhhh!" or "Daaayum, son!")

"You're such a Mary Sue, Shelob could use you as bait!"

"You're such a Mary Sue the entire fashion industry went broke trying to replicate your outfit!"

"Hey, Glitter-brain, I got a message from Aphrodite for you. She says if you make one more canon character fall in love with you, she'll come down here and strangle you herself!"

"You're such a Mary Sue, you could feed an army of minis for a month!"

"You're such a Mary Sue, even Voldemort fell in love with you!" (Because Rowling said he is literally incapable of love, if anyone needs a reference.)

"You're such a Mary Sue, artists had to invent another color wheel just for you!" (And then another... and then another...)

"You're such a Mary Sue, your breasts could be used as a floatation device!"

"You're such a Mary Sue, we could use you at a disco!"

"Yr sch mry s ll th vwls rn wy frm y." (You're such a Mary Sue all the vowels ran away from you. Yeah, I know it's not the best.)

"You're such a Mary Sue, Noah used you to get all the animals aboard!"

Meh, I was kind of stretching for the last few.