For example, a try/catch in V8 triggers deoptimization for the entire function it's in, while it might not in other engines. So this leads to many developers avoiding try/catch in performance critical code.

This ends up with them avoiding it in general usage, which means that now "avoiding try/catch" is considered a general purpose performance tip in javascript, even though it might only apply to one engine (and the v8 team has expressed interest in trying to stop that deopt)

This might be a bad example, i'm honestly not sure how try/catch performs in other engines, i just know it deopts in V8. But the fact that i don't know if it's a javascript thing or a V8 thing speaks to my point.