Everything about it. The only positive is discarding of some things you bought thinking you would use them only to move to the new place and replace them because you find you need them here.
They (the mysterious "they") say you should act like you are moving every 5 years and discard items that you haven't used or worn.
My wife detested clutter and would force the annual purge. One time I was being uncooperative, ONE TIME!, and she told me to go sit on the bed and she began to play that game "Defend Your Stuff" with me. If I could defend it, it stayed, if not, it went in the donate pile and I sulked. I gotta say, it was nice having a clean and well organized closet but I wasn't letting her know. I'd make sure she'd see me in my closet all sad and ask me what's wrong. I'd stick out my lower lip and say "I miss my cowboy boots".
We'd just gone through this annual purge and donated a bunch of clothing and among them was this t shirt that my wife hated. She'd ask me to get a Christmas garment of some kind so I ordered this long sleeved t shirt of this nasty looking raunchy reindeer holding his package with the caption of "Yo Santa, Jingle These". She'd not seen it until I debuted it at our annual Christmas dinner we hosted for 4 couples that were friends of ours. To say I wasn't a hit would be a gross understatement, I got the real look, not the one she used to just get my attention, the real one.
So, it's about two weeks later and we're going to lunch and as we're sitting at the light waiting to turn left under the interstate and I look over and there's this panhandler wearing my shirt. I exclaim "holy ______, that bum's wearing my Christmas shirt!!!!!" She just calmly looks over and says "he looks a lot better in it than you did". Then she added "look at it this way, You don't have to feel guilty about not giving him anything because you already did". Every time we'd go through that annual purge, that story would put us into fits of laughter.