emotivating's reply: You never saw the Mario movie?
It’s quite simple, really. Look at what Mario and Luigi are wearing. They’re obviously builders. In fact, builders who were contracted by Bowzer to build ‘Bowzer World’. Instead, they spent all of their time shrooming and were too stoned to build ‘Bowzer World’ properly (Would you be able to build while flying turtles were everywhere and army helmets walked about your feet?). Their foreman (that guy who throws hammers) was pissed. So instead, they built what they could in their oh so wasted state. They stuck pipes in the ground, random bricks in the sky, and dug holes everywhere.
Once they had finished building and came down from their mushroom high, they realized they hadn’t been paid. So that’s where the game begins. They’re trying to get their payment from Bowzer. But alas, his mushroom plantation tempted them before hand. So, instead of simply walking up the path and knocking on the door, they became lost in their hallucinations.
As for Bowzer, wouldn’t you be pissed off enough to develop Wallh@x if there were two stoned Italian guys running around your yard jumping on your topiary animals, smashing your turtles, and every so often, riding your dinosaur?