You didn't wear a mask? You better bet I have a hostile attitude toward you. It's entirely possible you passed on the virus to some stranger who walked by you in the grocery store who later died.

No, nobody ever proved masks are ineffective. That's just some oddly dumb fake news some people are spreading. But should you have abdominal surgery sometime, feel free to tell your surgical team they need not wear a mask because you don't believe in them. They'll still wear them, but you'll give them a good laugh.