In order to determine why I looked at other characters with a sad back story; ones that I didn't create.
One character who has a particularly emotional back story is Carl, from Up. His back story is one that, though brief, tells of a life-long love and heartbreaking loss. It inspires tears and sympathy. Something that was proven in class last week, when the short flashback series was played in class and we only got half way through it before several girls in class started crying.
His back story sets up the plot, why he wants to go to that particular place. It also makes the viewers feel sympathy for him and makes viewers root for him to succeed. Without it, he would just be seen as a bitter old man trying to escape being sent to a retirement home.
Another character with a sad back story is Neal Caffrey, from White Collar. His back story boils down to an absent-father, who was not as upstanding a citizen as Neal was lead to believe, and a mother who was not particularly supportive, (basically, physically present but emotionally and psychologically absent). Neal runs away when he discovers his dad was a criminal and uses his natural street-smarts to make money, though not always legally.
His back story sets up a kind of excuse. Growing up with out a father as a role-model and a mother who was only physically preset, it can be said that it was only natural he would turn out the way he did. And since he had always idealized his father as a hero, finding out his father was a criminal, he could have subconsciously thought that, that was his own future as well.
It also adds an interesting dimension to his relationship with his partner. Perhaps, meant to further establish Peter's role as a father-figure.
A third character who has a relatively tragic back story is Abbie from Sleepy Hollow. When she was young, she and her sister saw a pretty creepy thing. No one believed them, so she lied and said she didn't see anything. Her sister was committed, because she didn't change her story. And Abbie ended up causing a lot of trouble, juvenile delinquency and dating bad boys kind of things.
Looking at characters with dark back stories, it seems like it not only sets up why they are the way they are on a psychological level but also can add foreshadowing.
Abbie has to face that the things she saw were real and try and mend her relationship with her sister. Neal has to deal with his father and decide whether to follow in his father's footsteps or follow the lead of his father-figure, Peter. Carl takes "Ellie" on one final adventure, the one he promised her, and in a way he gets a son/grandson-figure that he had been missing.
So, maybe that is why I do it. Or maybe, I just find happy back stories dull.
As for why I usually use the parents to create the negative back story, well that is easy, there are very few people who influence your life as much as your parents. Even when they aren't there, it influences you, as it did with Neal. And there is nothing more tragic for a child than losing one or both their parents whether their parents die or are just absent, as is the case in many Disney movies (Bambi, Beauty and the Beast, Snow White, Cinderella, Tarzan, The Lion King, Mulan, Hunchback of Notre Dame, The Little Mermaid, The Princess and the Frog, Atlantis, The Fox and the Hound, etc.)
As for why I usually use the parents to create the negative back story, well that is easy, there are very few people who influence your life as much as your parents. Even when they aren't there, it influences you, as it did with Neal. And there is nothing more tragic for a child than losing one or both their parents whether their parents die or are just absent, as is the case in many Disney movies (Bambi, Beauty and the Beast, Snow White, Cinderella, Tarzan, The Lion King, Mulan, Hunchback of Notre Dame, The Little Mermaid, The Princess and the Frog, Atlantis, The Fox and the Hound, etc.)
What other characters do you think have sad back stories?