Here's a blog featuring wrongly used quotation marks.
It is a common error to use quotation marks for emphasis. They are not for emphasis, they show a quote, or irony. For emphasis you use underlining, bold, or italics. Or upper CASE, though that's a bit blunt. In text-only environments you can use *asterisks*. "Don't" use quotation marks.
You "must" look both ways before crossing the street.
The man hollered: "look out, there's a car!"
Wow, what an "alert" pedestrian, call an ambulance.