Comment on Guide to Writing Fanfiction by EmpressTuiLa
This is great advice, but I want to say two things. 1. If you give a character a tragic past, don`t make them a whiny character. 2. Male Mary Sues are also called Gary Stus. Still, thank you for a good definition of Mary Sue! For a lot of people, the definition of a Mary Sue is so broad that every OC could potentially be a Mary Sue
1. True. 2. Funfact I didn't know! Thanks 
Definitely, many have not a clue.
You`re welcome. I was going to elaborate by saying 'Tragic Past? Mary Sue. Powers? Mary Sue. Weird colored hair? Mary Sue'.