In Diablo 2 Resurrected, henceforth referred to as D2R, you find a ton of weapons and other items throughout the course of the game. There are 7 playable character classes, and so some characters might find items that are only beneficial to other characters. For example, the Barbarian might find a wand that gives +1 to all Necromancer skills. That's obviously useless to the Barbarian, and the game provides a way of transferring these items to other characters via a shared stash. 

The shared stash is pretty massive, but it fills up very quickly as you play through the game. First, it seems like there is an endless amount of space available, and you start hoarding up every item you find that is even remotely plausible to be used later. Things like "I don't have a Martial Arts Assassin now, but if I ever start one later, I'll want to keep this."

The result is that the stash ends up 99% full most of the time. You end up playing through the game droppings items in your inventory onto the floor just to pick up the new item that an enemy left behind to see if it's worth keeping.

Many players complain about this, and they have thus requested additional shared stash slots from Blizzard for the game.

But there's a fundamental mindset problem with wanting to keep all the items. They end up not creating value, but instead end up spending all of their time as clutter. The mindset of clutter is always "if I ever need to do this, then I'll have it ready." It's a mindset based on thinking that being ready for something creates opportunities to do that something later.

The reality is different. Clutter doesn't create opportunities, it prevents them.

Freeing up your inventory, meaning your real-life closet, garage, and dresser, means creating opportunities.

In the game, this is expressed as the opportunity to pick up every new item that drops instead of passing them up all the time.

In real life, this means that you no longer have to manage your inventory and say "no" to things because your closet is full of skis, rollerblades, and bowling pins.

So, the lesson learned from games is this: free up your inventory, and create opportunity.