7. He's An Unlicensed Medical Practitioner
According to the realistic medical drama Scrubs, it takes eight years to become a fully qualified Doctor - it is a profession which requires unwavering commitment and high levels of intelligence. Mario is a plumber who can often be found swanning off on trips into space or engaging in kart racing... where exactly did he find the time to become qualified? The answer is that he didn't. I mean what kind of Doctor would prescribe a selection of pills simply because they are the same colour as a virus? Does a virus even have a colour? A doctor would know the answer to that, Mario does not. If he wanted to call himself a Doctor Of Plumbing, then perhaps I would let him get away with it, but he is out there dealing with real diseases. Who knows how many he has already killed?