The original Super Mario Bros. for the NES is something of a Rosetta Stone for adventure games, informing virtually everything that followed it. It's a simple tale of an underdog hero overcoming impossible odds to rescue a damsel in distress from an evil monster. Pretty simple, right? Wrong. It's a tale of corruption, genocide, greed, and overflowing sewage. And Mario's the bad guy. These are the horrible truths about Super Mario Bros.
Let's say you're a Goomba - you don't exactly have the best life: you're short, you're weak, anyone who touches you dies, and you're named after an ethnic slur. Luckily, all you want to do with your time is peacefully walk across the world. You never target anyone, you mean no harm to a single soul - you're actually a peaceful, benevolent creature (who happens to look like the kingdom's primary food source). Hell, you don't even have any arms.
Suddenly - you get smashed. You're dead. Wha - What? Why? Who? Well, confused dead Goomba - an Italian plumber just crushed you to death for no goddamn reason. He jumped on your skull and flattened you because he felt like it. You were never trying to do anything to him, but because you dared to walk in his general direction, he ended your existence.
Mario is a violent nutjob. Very few of the enemies in Super Mario Bros. are actually trying to kill him. Sure, there's the Piranha Plants, the Thwomps, and maybe even the Hammer Bros., but the vast majority of the enemies Mario kills are just out for a walk: Koopas, Goombas, even Bullet Bills are essentially innocent creatures that can't control when or how they're launched. So why does Mario do this?
Because they were in his way. That's some Dexter-level thinking right there.
What do we know about Mario? Quite a lot, actually. He used to be a carpenter named Jumpman, but then changed his name to Mario and became a plumber. A shitty plumber. Maybe the worst plumber in a generation. How do we know this? Look at the world around you.
There are pipes everywhere in Super Mario Bros. Giant, worthless pipes. Some go nowhere. Some have fire-spewing plants living in them. Some traverse worlds - some just go directly into the ocean. They do all sorts of things - but none of the things pipes are actually meant to do. The sewage situation in the Mushroom Kingdom has got to be an absolute nightmare.
So how did the world's worst plumber land the biggest plumbing gig ever, given he clearly has no idea what he's doing? Well, it sure does help that you're dating the scion of the royal family. He probably used some cheesy line like "We both know I'm great at layin' pipe" or something, then convinced her to let him take care of the plumbing for the entire kingdom. Now there's a sanitation disaster that would require years of clean-up and a complete overhaul of the kingdom's insane excuse for a plumbing system, and it's going to cost them a fortune to fix.