Why, you ask?
Because writers write about what they know, including the people they know. Especially the people they know.
They write about their fathers and how those fathers took one look at math assignments, handed them back and said children should do their own story problems, thank you very much.
They write about their mothers and how they were a (scary) force to be reckoned with whenever they got their Wyoming cowgirl on.
They write about their brothers and how they used to dress those brothers up like girls and make them fetch the mail so the neighbors would think those brothers were actually sisters.
They write about their dogs and how those dogs knock over Christmas trees in the backroom when they think no one is looking.
They write about their mothers' dogs and how their mothers' dogs steal pork chops right off of dinner plates when they think no one is looking.
They write about sons and how those sons all went commando to the pediatrician's office that one day.
They write about husbands and how those husbands cheer — year after futile year — for the reliably awful Chicago Cubs. (Cue his favorite joke — "Everyone can have an off-century!")
And yes. Writers write about friends that they made when they were both 11 years old.
Writers will write about how super nerdy the two of you were in the sixth grade, reading "A Wrinkle in Time" like it was the Holy Bible and playing "The Green Berets" on your ukuleles. (?!!) Or how embarrassed you were that your mothers showed up to register you for your classes like you were babies on the first day of seventh grade. Or how you both ran for class office in junior high school and lost, which caused the two of you to cry and cry and cry. Or how you got mixed up and accidentally washed your hair with Avon's Skin-So-Soft bath oil instead of shampoo.
Writers will write about that day the two of you got busted eating tacos (with a side of frijoles) at Taco Bell by the writer's dad when you were both supposed to be somewhere else. Or how you used to watch Milo White snarf Jell-O in the school cafeteria. Or (most famously) how you single-handedly took down a tree at the Provo High School driving range, which caused your driver-ed teacher, Mr. Moon, to regard you forever after with both respect and fear.
Writers, in other words, will write about YOU.
Are you up for that?