To be very boring and serious...
My mother in law is a hoarder. She lives alone (surprise surprise...) in a house that has four bedrooms and a study, but there so much crap there that I feel claustrophobic when I'm there.
PLUS she's got crap in a storage unit that she can't afford... And still tries to bring crap up to our place "because you've got so much room". Those of you who have seen my shed will understand how ridiculous her place must be.
Personally, I've always been limited by space and money, so when we began to earn enough to buy a place with a big shed (7x9m + mezzanine), a 12x5m machinery shed, and a 7x3m converted stable, all on an acre, I went a bit beserk, and overfilled the place... I think my worst was 45 bikes and 42 cars...
After a while, I realised that:
A) Even if I lived to 150 years old, I was never going to finish all o the projects I had;
B) Despite my best efforts, stuff was deteriorating;
C) I was sick and tired of tripping over stuff;
D) The effort of keeping track of it all was really quite draining;
E) There was a hell of a lot of money tied up in all of these unfinished projects;
F) These unfinished projects were draining a lot of my income, which stopped me doing stuff that I wanted to do;
G) There was no way I could use all of them anyhow (I owned seven Pre-75 250s and five Pre-78 125s at once, for example...).
H) I was basically turning into my mother-in-law...
I had all of the excuses, of course: "If I sell this, I'll never find another one", "I bought it to save it", "I always wanted one of these", "The old stuff is cooler", etc etc, but something had to give - so I started selling stuff - some of it was just junk, some of it definitely wasn't...
My wife even objected: "You will never find another one", and stuff like that.
But you know what? Having less "stuff" is a huge relief, and I haven't regretted a single sale.
There's still a long way to go, and the juiciest fruit has already gone, so progress is slower and more difficult, but I can live with that.
We're ahead on the mortgage, I've been able to afford two brand new bikes since 2011, I have more time to spend with the family, the Wife is happier, the kids have more space, I've got a lot more financial flexibility, the neighbours are happier, and because of all of this, I get to ride more often.
I never considered myself mentally ill, but my mental health has definitely improved since I have recognised that my collection was simply cluttering up my life.