The accent thing doesn't just apply to Spanish-speakers speaking English, that's for sure. I have a friend from Argentina, who, when we first met, asked "You speak Spanish?" When I replied, "No, Francais - mais un petit peau," he replied, "Ah, no Francais, me. You speak Mexican?" Clearly to Argentinians, they speak Spanish, Mexicans speak their own language.

There's pretty much nothing folks normally say that make me want to smack them. Fight the urge to correct them? Sure. (In instances that I DON'T correct them that is.) Smack anyone? Nah.