Chicken Soup for the Sue
Wouldn't it be fun to fight alongside the good guys or cackle evilly with the bad guys? It's tempting to make a character that fits in a with a group in a TV show, movie or book. This character could be friends, lovers, or children of characters admired or feared in a story. That connection to someone special can mean so much. For example, say that the rpg was based on Teen Titans. This is a cartoon that brings together teenage superheroes who fight against evil. You could join the team and kick the crap out of Mad Mod. Maybe you think Robin is cute and being his girlfriend would be great! He's so strong and brave. He's also troubled and you can ease his troubled soul. Or, say he and Starfire had a kid and you were that kid. You would have the combined powers of martial arts, flying and cooking stuff just by looking at it.
If this is not about a canon or being connected to some other important character (like the child of a king and queen or a fugitive running from a vampire slayer), maybe just having a cool super power is enough. In your own life you have no super powers but it would be neat to do things that are impossible. I've always wanted to fly, shoot laser beams from my eyes, throw a car at someone mean, set a house on fire with my mind or know what everyone around me is thinking. Having the upperhand is an intoxicating feeling. This idea of having a great power extends to just being able to say how you feel without any consequences. Think of how satisfying it would be to shut people up and be the one in charge of a situation that's normally out of your control in real life?
Just being able to not be you or a better you is intriguing. You can be the person who paid better attention in science class and now can build a robot army. You can have that floor length auburn hair you've always wanted instead of that mousy brown you really have. No one appreciates your personality in real life but in an rpg, every character is gathering around to appreciate you. They don't see your faults because in this idealized rpg character, they aren't any. Your confidence is a legend and you're a magnet for good things. You are unique and everyone accepts you for that.
After reading all that I bet you think I must have developed a soft spot for Mary Sues. Fuck that. No, I haven't. If I did I'd be using those arguments to defend them. They all sound logical, don't they? They all explain why Mary Sues exist. Mary Sues are born out of emotional baggage. Things that are missing offline are fixed in the rpg. It's a little like group therapy only it's thrust upon those of us who don't give a crap. My friend Freaklin Gout coined the best term for this behavior: Emotional Masturbation.
"Emotional Masturbation? That sounds harsh."
I just read your thoughts... at least if you're a Mary Sue, that's what you're thinking. And it's the honest truth. Role playing involves taking on a persona and telling a story but rarely does a Sue want a story that isn't their own. After playing in rpgs for 10 years and owning several clubs I have seen many Mary Sues join an rpg believing all the other characters are created for them only. Certainly people playing Buffy, Giles, Willow and Xander are all aching to owe their lives to the new potential slayer, Shadow. She's really the forgotten child of Anya and Spike so why wouldn't they all leap over each other to smother her with love? She even has the power to bring Doyle back from the dead and make him her boyfriend. And why would I, playing Warren, want my ass handed to me over and over again? Surely I joined this rpg for the sole purpose of playing a floor mat.
That was an example although it is dreadfully close to the shit I've seen. I have some other examples of Mary Sues who attempt to bend or ignore the rules to make themselves fit in with the heroes. The first is from a Harry Potter rpg where all the canons were taken away. The timeline was set 20 years after the final book and no one from the book could be included in the rpg. Even children of characters we knew were a big no-no. So what happened? On a weekly basis people applied to the rpg asking if they could be child of Harry and Ginny, Harry and Cho, Hermione and Ron, Hermione and Viktor or Malfoy and whoever was left. In a Buffy rpg the only canons allowed were Faith and Giles. A stubborn Suethor who only played Dawn demanded actually joined the club and asked to play Dawn. When she found out she wasn't allowed to, she had a hissy and actually told the club owner every Buffy rpg should have a Dawn and the owner wasn't being open minded at all. In another Buffy rpg an honest Suethor joined the rpg and promptly made an ooc message to announce she would only play in this rpg if she were allowed to play Spike's girlfriend. She'd ignored the very post ahead of hers where two Suethors were already locked in a bitter battle for Spike's love.
Being skilled or magical above everyone else must be hard when four or five others have the same idea. I've seen Mary Sues bickering over who gets to save the day. Usually one leaves the rpg because she overstepped the God moding rules in order to be more awesome than the rest and she doesn't want to admit what she did wrong. Why should she? She was in the right because Mary Sues always are, right? Surely everything they say about themselves must be upheld. One Mary Sue in a Harry Potter rpg kept telling us how sexy she was and how all the girls hated her beauty. She created a reality around her character where those of us playing female characters were incredibly jealous to even be around her.
Everyone had better play along with a Mary Sue and indulge her in her emotional masturbation. At least, that is rule one in the Mary Sue book. It doesn't matter to her that you may actually want to write a story. Isn't she the focus of your story anyway? You weren't really doing anything before she came into your life anyhow. She needs copious amount of attention, love, understanding and ego boosting.
There is no defending her and her selfish ways. She is only there for herself and no one else. Try as you might, all that pompous buffoonery she commits just ruins everything she touches. And don't ever let her touch you. You have no idea where her upperhand has been!