Bags are big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big bags actually are. Outer space is nothing compared to the inside of an adventurer's backpack (with apologies to Douglas). The wondrous thing is that - even though players are allowed to equip not one but many of these hugely incomprehensible, vastly improbable and wholly fantastical containers of every otter spleen and troll bunion that you grab as you roam the lands - the biggest complaint about bags is that they don't have enough space.
The humble bag is the stalwart companion of adventurers everywhere, yet it goes unloved and unnoticed. Unnoticed, that is, until the day the adventurer needs to pick up that ultra-rare epic item and finds that they don't have any bag space.
The Encyclopaedia Melmothia states that the average adventuring bag contains 16 slots, of which one slot can contain any item, up to and including an armoured chest piece. Let's take a very rough estimate of a solid plate chest piece as being 1.5ft x 1.5ft x 0.5ft in size, or 1.125ft^3. Assuming perfect stacking, we can fit sixteen of these in a backpack without air gaps between them, so that's a volume of 18ft^3 for the backpack or approximately 510 litres. There's a special place in the Inferno for those of you checking my calculations in order to nitpick some minor mistake in this stupid example. Now, the bigger, more ludicrously sized real world backpacks that I could find from a brief search on Google were between 200-300 litres. So your average adventurer is carrying a pack which is about twice the size of that. Actually I'm wrong: adventurers are generally carrying four or more of these bags, which is about 2039 litres, or enough space in which to park a good size family saloon car.
Why is it that you can't put items into a bag that is currently being carried in another bag? Well, imagine the potential recursion there, it's like 'crossing the streams' of a pair of proton packs: if you could put items into a bag that was already in your inventory the first thing you'd do is fill your sixteen slot bag with sixteen slot bags; each of those bags could hold more bags, until eventually you'd have enough space to hold the entire world, at which point it would rip a hole in the fabric of space-time, opening a portal into the dark recesses of the cosmic nether, from whence Beryl Reid will come forth and dance the seven steps of chaos that will bring about the fiery doom of the universe.
Curiously, to my knowledge, nobody has considered the concept of 'bags as weapons'. Considering the cubic volume that each slot of a bag can contain, all the budding Lord of All Destruction need do is fill each slot with iridium. The bag is now so heavy that, assuming they could find a trebuchet powerful enough to fire it, it would not just breach a castle's walls, but entirely obliterate it and several miles of surrounding countryside. And that's just a two slot ladies purse... Find a trebuchet powerful enough to overcome the planet's gravitational pull on your main backpack, and you would cave-in half a continent with a crater to rival that of the Barringer Meteor. The strange thing is that in many games these adventurers, being of that stock that can perform heroic feats, can carry these backpacks around without batting an eyelid. So all they need to do is run up to the top of the cliff (for they can run everywhere when carrying that weight) and leap off, cannonball style into the castle beneath. Judges award extra marks for style and crater depth.
So don't let me hear you complain about 'falling damage' either, because technically when you jumped off that small hillock, you shouldn't so much have landed as plummeted, thundering through the planet's crust on your way to the core.
Technically, with that volume of space, you could get inside your own bag. You'd only take up a couple of slots, and then all your friends could carry you around! Better still, you could all get in, take a slot each, stick a couple of wheels on and you've got yourself a mode of transport. Just whip out that horse you conveniently keep in a slot in your handbag, attach some reins and away you go.
Slots themselves are curious defiers of the nature of space: some items such as potions will stack, such that you can carry enough in a single slot that it would probably match the volume of our example chest piece, but then some seemingly random small items, such as fish eyeballs, won't stack. Thus you have an entire slot taken up by something that would comfortably fit up your own nostril. Yes, it would fit comfortably. No, don't ask me how I know this. It seems strangely accepted throughout the MMO world that you can have a sixteen slot bag full of sixteen pieces of heavy plate armour, or the same sixteen slot bag full of sixteen fish eyeballs.
Bags are curiosities for sure.
So next time you run out of space in your bags, remember, you're actually getting a pretty good deal in general, and if you continue to complain then Beryl Reid will come and smack you with her handbag.
And you don't want to know how many slots that thing has.