Everybody forgets.
It's a reoccuring thing, even for Wizards. Muggles forget their anniversaries and other people's birthdates. Wizards forget spells. People forget their histories, their cultures, their decency. It happens.
Everybody falls sick.
It's an unavoidable thing, even for Wizards. Muggles get the flu, get chicken pox and pneumonia. Wizards get the Twirling Madness, get Green Fly. People fall into mob hysteria, get infected with memes almost in a daily basis.
Everybody dies.
It's inevitable. Muggles get killed in car crashes, airplane crashes and old age. Wizards die of duels and plain bad luck. People and societies get wiped out, become extinct.
People bleed, wizards bleed, Muggles bleed. They and we feel pain, and yet we hold them to a level lower than us. It's as if magic was the province of 'higher beings' and that Muggles are only slightly better than animals.
Remember this, Wizards -- it hasn't happened yet, but Muggles are catching on. The only difference between both our peoples is that Muggles get better and better over the years, while we stagnate.
That's right -- the wizarding world is stagnating. It's a slow and ardous process. Muggles invent faster and better things, year after year. Wizard spells stay pretty much the same. They're breaking into new ground, changing their ideas of automobiles almost by the decade. Our broomsticks, despite being faster, are still the same old design. Their medicine, though slower and cruder than ours, are catching up. The latest thing our medimages are thinking up is better poultices for hippogriff bites. Better poultices.
They already know slightly more about the universe than we do.
And their technology allows them to store a small library inside a box of metal and plastic, while we stick to books. They have something called an "Internet", and some of the crackpots over there are prophesying that network's existence over every square inch of our planet!
And we do nothing but keep them in the dark about our existence, playing them off like children. "What fools," your Ministry of Magic gloatingly cackles, "They don't even believe in magic, even when it stares them right in the face!"
Remember this, Wizards -- they're doing pretty well by themselves, and they don't need magic. At all. They don't need us and our magic, but we need them -- I mean, who else will grow food for us, provide us with the raw materials we need for our precious studies? They do. Even the most advanced tool of magic was born of the handiwork of Muggles. Those silly stupid Muggles we mock and fail miserably to blend into.
I mean, we can't even blend in properly. Wizards, the highest order of men, unable to do something Muggle spies and undercover operatives have been doing for hundreds of years! Even our best wizards treat them like how Muggle Britain treated its colonies -- like things no better than animals.
I'll tell you what's wrong with wizardry. Hubris. Arrogance beyond measure. We have families disimissing Muggles as 'inferior' and even the best of us treating them like suckers. Even the greatest of us all, a young strapping man named Dumbledore, can't relate to any one of them. Not even his rival Riddle can. Or the hordes of "Muggle Researchers", who go along their studies like the Jane Goodall with her chimps.
They aren't chimps, people. They're people. Like you and me. And unless we give them their due respect, they'll forget about us.
And heaven forbid if they stumble upon us again, like they did when the Inquisition happened. Then they had stakes and flames then, tools we could easily counter. Now they have anthrax and gamma rays. Remember Nagasaki and Hiroshima, friends. None of the wizards there survived. And Mugglekind is so prone to destroying things unintentionally.
Beware, wizardkind. Beware.