How do you backstory?

When I play tabletop RPGs such as D&D, I'm usually a backstory-synopsis writer, 3-5 pages worth. If I think it'll be a long campaign, or even a few sessions, I write waaaaay too much backstory. Why? Mostly because it's fun. I like to leave dangling threads for the GM to play with, but I know 99% of the time nobody is going to read the history but me and the GM. (And yes, I'm as bad with joke campaigns as with serious ones.)

"I'm Stabitina, the stab-everything barbarian. I stab the water with
my shortsword and shout 'That's for the time you tried to choke
my cousin!' It does 14 points of tasty damage to the hot water,
and I gain the satisfaction of revenge."
"...Yeah, sure, whatever. The barbarian stabs the tea until
it tastes good."

On the other hand, a lot of the players I play with are more along the lines of "Yeah, uh, I came from, uh, the western plains, and don't like bananas or orcs"-style backstories. They roll the stats and have some kind of concept as to the type of character they play. Think more along the idea of a pitch than a short story: maybe thirty-five words of who the character is, what their motivation is, and why they've joined the party.


Both types of players are great to play with. Most of the fun of the game is roleplaying, and learning one's own character along the way is as much fun as writing a story with beforehand.

What kind of backstory style do you follow? Lots of story? Make it up on the fly?