Food for thought:
Mario is a real dick if you really think about it…here's why.
~Mario Kills Countless Enemies – Who Aren't Even Trying To Hurt Him:
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. Luckily, all you want to do with your time is peacefully walk across the world. Uou mean no harm to a single soul 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
~Mario is a Terrible, Negligent, Crooked Plumber:
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?
~Mario Is Bankrupting the Entire Kingdom:
We've established Mario's looking for an easy buck and doesn't give a damn who he screws over, and also he's got a hell of an in with the royals that makes him virtually bulletproof. So what more could he do to ruin this poor kingdom? Oh, I dunno, maybe ROB IT BLIND?
Why the entire wealth of the nation is jammed in bricks. Maybe Koopa tried to hide some of it in bricks, assuming no one would be crazy enough to go around punching them all. What matters is Mario collects all of the gold for himself and shows no intention of ever giving it back.