Hoarding. Something dragons do in stories, squirrels do annually, and something a lot of people do throughout the world. Americans are especially good at it (though anyone can be good at it, rich or poor, it doesn't matter).
The official quick definition of a hoard is "a supply or fund stored up."
How can hoarding hurt us? Depending on what you are hoarding it can be unhealthy if it is filling up your house (like newspapers, pizza boxes, trash, etc).
If it is money and funds, it can be unhealthy spiritually because you can begin to trust in those and the numbers in your bank accounts rather than God.
If it is stuff, you can get caught up in taking care of your stuff and seeing it has what defines you rather than being a child of God.
If you have a lot it is easy to forget how little many have. It can desensitize us to others, to needs crying out throughout the world.
It can make us selfish and childish and spoiled. A child who has everything doesn't know how to be grateful.
We can easily forget what life is really about.
And finally, it can be the vehicle by which you choose the wrong path rather than Jesus, a path that will send you straight to hell.
There's nothing wrong with stuff, with money, with having things.
Just make sure those things don't have you.