Stupid sexy Flanders!
You might have noticed in movies that teachers or the villains will call the main character by their last name. This can be confusing to some people from different societies that don’t understand the concept of a last name. However, in general, it’s not uncommon for people to call others by their last name, friend or foe alike.
It’s not polite or impolite to do so, but you wouldn’t want to call your boss or anybody in a position of power only by their last name, at least to their face. But for the most part, it’s safer to call someone by their first name, or at least add a Mr. or Ms./Mrs.