Why do we even have that lever?

The maze used to be an ornamental key-rack. Or - well, it still is, technically.

Why is this room full of ruined swords?

 

Because it has the contents of the old armoury! You know, from before that wizard took over with an army of magically uplifted monkeys who were too small to use the swords.

They're all going to be melted down to make weapons and armour sized for monkeys.

Why is there a hallway in this person's house that is full of extending and retracting crushy stone pillars that move in a wave and squish you if you don't hide in this hole??

 

That´s not a hallway silly, that´s part of a production line. The pillars have stamps on the end that get pushed into sheets of material on the "floor" however, the part that made the floor move broke.

Why is this area full of uncontained flesh eating plants?

 

It was an herb garden. About fifty years ago, an evil vegan wizard with a world domination plan did a magic ritual to cause all plant life to rise up and attack the fleshlings, and the druids involved in cleaning up the mess after she was defeated missed this spot because of the castle's isolation and defenses.

Why does this treasure chest explode in your face if you open it?

 

It was a gag for children's birthday parties. Presents were supposed to launch out of it, but age has eroded both the spells and the components into a precarious mess that explodes on contact.

Why do the books here have teeth and try to eat you if you read them?

 

They're actually living, book-shaped organisms (with text that looks real at first glance, but turns out to be something like this nonsense when looked at closely) that moved into the castle library after it was abandoned. They ate all the real books and took over the shelves.

Why does going through this portal swap your sex and alignment?

 

It was considered a revolutionary medical advancement in gender affirmation technology, but the personality adjustments were an unfortunate (and unfixable) side effect. Later iterations weren't ever developed because they got their funding cut, so the original test portal got shuffled off to a locked room and forgotten.

Why does this section of the ramparts fall into an endless void unless the flagstones are stepped on in a certain order?

 

The castle's previous owner bred shapeshifting mimics as pets. They've gone feral, but they're social and move in a flock, which currently happens to be in the library.

Why is there a thing that looks like a save point but attacks you if you interact with it?

 

It's the other way around. Like many people, the inhabitants of this area adopted the image of a local apex predator as a symbol of themselves and their community. Many impressive taxidermy displays exist, and after it became illegal to hunt them due to dwindling populations, realistic fabricated depictions. It's a tradition to touch them for luck and strength when you're embarking on a difficult task. Unfortunately, like so many conflicts between humans and other apex predators, the creatures themselves were extensively killed and/or driven out of the region. For a long time they were thought to be extinct in this area, but recently they're starting to make a comeback. It's really quite exciting.

Honestly, if these crazy adventurers don't know enough about local wildlife to be able to tell the difference between the real thing lying in wait and a stuffed one, they're pretty much beyond hope.

Why does this tomb have pressure-activated traps that drain all your mana/magic?

 

Latent magical energy has a corrosive effect on the preservation enchantments used throughout the catacombs to prevent the bodies from decaying in an unseemly and smelly manner and stop the silver filigree inlays on the sarcophagi from tarnishing. It's just easier and less risky to drain the magic from visitors when they come in than to send someone in to repair the spells every time someone goes through to pay respects to the dead.

Why do you have to jump across a series of small moving platforms over a pit of spikes to get to the next room?

 

Why are you going through the service area, dummy? It´s supposed to be a dumbwaiter type deal, the spikes are to discourage assassins from sneaking in and getting important guests that way.

Why is this room full of poisonous fog that smells like burnt oranges?

 

Originally this room was used to manufacture items and the platforms were a sort of conveyor belt. Products deemed "faulty" were pushed into the spikes. However the company went out of business and never shut down the factory properly.
Why does the boss at the end of the dungeon not leave the room?

 

This was originally a manufacturing plant for air fresheners and disinfectants. After the place was shut down the chemicals started leaking out and don't mix well together.

Why is the floor here covered in glowing stones you have to arrange in a certain order to get the door open?

 

Why would he? there´s room service, and once in a while, idiots to fight.

Child safety. The room used to house dangerous workspaces they didn´t want the kids to get into.

Why are there giant spiders all over the place?

 

The religious order that this temple belonged to had secret sigils that were known only to initiates above certain ranks, and sealed off higher-security-clearance areas with passcode systems that required you to manipulate a large magical sculpture into the shape of the appropriate sigil to pass, thereby demonstrating both your rank and your devotion. With the loss of many portions of the sculpture that didn't stand the test of time as well as stone did, its detection algorithm for whether the right sigil has been entered has gotten kind of janky, so it works as long as things are correctly positioned along just one of the original three axes.

Why does this door only open if you play the piano next to it?

 

It's actually a password lock so that people can't get in if they don't know the password.

Why do the paintings shift around the walls of the room?

 

The previous owner paid a ton for their kid's piano lessons, so they were damn well going to force them to actually practice no matter what it took.

Why do all these four-entrance revolving doors only move 90° clockwise at a time, and then switch to only moving 90° counterclockwise until you use them again?

 

Because the evil wizard knocked out some of the supports and some sort of monster got into the space under the floor. The flagstones move a bit when you step on them, and if you step on them in the wrong order they settle in a way that pokes the monster and wakes it up and it breaks another support and the whole thing falls into the deep long pit that used to be the moat.


Why does this Dark-aligned creature have instadeath lasers in his house?

 

Ooooohhh man, the fucking paintings. You seriously do not want to get involved. Long story short, the people who lived here had a rocky marriage they expressed through art patronage, of all things. Awkwardly, one of their kids was really interested in painting. That may have actually been part of how they alighted on this topic of argument in the first place. In any case, the kid did grow up to become a rather accomplished painter. And uh, well, let's just say nobody could ever decide on which painting deserved to go where.

Eventually someone paid a ridiculous sum to have a wizard come out and make them rotate places periodically, just to stop the fights. It didn't work of course, and it really just looks pretty weird, but after that whole experience the wizard refused to go back there long enough to remove the spell for any sum. The whole family was actually blacklisted by the entire wizarding guild, so the spell's probably gonna be there for a very long time.

Why does this huge factory have many catwalks high enough that you could be seriously injured or die if you fell, but no guard rails? Are they trying to get sued?

 

Giant spiders are a critical part of any magical ecosystem! >:::OOO Their webs exist in multiple planes, and their primary nourishment is creatures they catch trying to move between them, such as lesser fae, demons, and undead trying to manifest in the mortal world. The reason giant spiders are usually found in places where the bounds between worlds are weak is because they're there to eat imps and the like trying to break through that could cause all sorts of problems if they were able to freely enter the mortal world in large numbers. And you keep killing these majestic creatures that are single-handedly protecting us from the spectral plague, you MONSTERS.

(leaving it blank because there are several unanswered ones already.)