Compulsive hoarding (or pathological hoarding or disposophobia or the Messie mindset) is a mental disorder marked by an obsessive need to acquire (and failure to use or discard) a significant amount of possessions, even if the items are worthless, hazardous, or unsanitary. Compulsive hoarding causes significant clutter and impairment to basic living activities, including mobility, cooking, cleaning, showering, andsleeping. A person who engages in compulsive hoarding is commonly said to be a "pack rat", in reference to that animal's apparent fondness for material objects.
Why is hoarding so bad? If I like something I just want a lot of it! All the time!