I've gotten counterfeit body wash (Shiseido Super Mild) and counterfeit microSD cards off Amazon, and, ironically, the only things I buy off amazon.com now are books, because if they're counterfeit, it'll be obvious, and it certainly won't cause me any harm.

Everything else I'd rather buy from the manufacturer (and pay the full, unsubsidised shipping cost -- not Amazon Prime) or a reputable distributor (digi-key/mouser for electronics, CS Hyde for films/tapes, etc). The prospect of having my eyes fried because of counterfeit PPE is kinda horrifying.