Sunday night before "Mad Men", I watched several episodes of "Buried Alive", a show about hoarders. The show is done with an empathic touch, no judgment. The ones with hoarder parents of small children are particularly heart wrenching.
A common thread seems to be having OCD, depression, and/or a traumatic event - death of a loved one, a brain injury.
My mother had (has?) a touch of the hoarding, which was controlled by being a military wife and moving every three years or so. But once they retired and settled down, the "might need that" gene took over.
Granted, there were no goat paths through the piles - in the house that is, the garage was a different story. She saved every scrap of fabric, every notion, every pattern, piece of yarn - no matter how small, and packed it into either a closet or the garage.
In the dresser and night stand department, Dad was allotted two drawers out of fifteen. She kept clothes that hadn't been worn in years, uncomfortable shoes, every card, photograph, and horrible craft project sent to her by friends. She seemed to think that a rejection of a gift, no matter how useless or ugly, was a rejection of the person who gave it to her.
(Real friends don't hold friends hostage over gifts.)
Food: there were roasts in the freezer that were eight years old, peaches and pecans from the late eighties. I once found a box of Rice-a-Roni in the pantry that was twelve years old. It had been moved from California.
Sometimes I yell at the TV when people are moving from their 2400 sf home into someplace bigger, because they've "outgrown" it. People - you don't have too little house - you have too much crap! (Judgment - yeah, I haz it. There it is, right on the end of INFJ.)
When I first moved to Florida, I spent an entire day cleaning and organizing the garage. Within several months, it was back to piles and paths.
I used to get mad at Mom when she couldn't find the Halloween decorations she just bought because they had been swallowed up by the abyss of the garage. She spent so much time (and money) looking for things and then having to buy more because she couldn't find them.
And she said I was wasteful.
Check out this site, courtesy of poking around the Unclutterer.