|"DON'T call me 'Teacher!' "|
In Canada we use titles only for those who have gained a higher title, like "doctor" (for physicians or academics), "pastor" in a church, etc. Mr. and Mrs. are used for the older generation, but this usage is wearing away in favour of first names in may situations where it used to be necessary. We also almost always add the last name; for example, I would call a professor from my university "Doctor Faber" or "Professor Faber," and never simply "Doctor."
In Mexico, on the other hand, anyone who has a title or a professional position can be called by that title, and most often is. Teachers, for example, are always called "teacher" by students and others in the community; even an accountant is often called "accountant" as a title. (As in, if you see your accountant, you could say "Good morning Accountant! How are you?") Names are usually excluded, but sometimes first names are added.
When I first started teaching here, I listened to all the students call me "teacher," and I assumed they simply forgot my name. So after I made a habit of writing my name on the top left corner of the board as a reminder (without drawing too much attention to it), I realized that they still always called me "teacher." At that point I realized that it was a cultural difference, and starting explaining to my students that in North American culture a simple first name was fine (these were adults only slightly younger than me.)
One day, however, one student explained that in Mexico it was a matter of respect; it didn't seem right to call a teacher by simple first name ("teacher" + [first name] is fine, even from children). When I told her that it just didn't make sense in English or Anglophone culture, she, along with others wanted to know how they could show respect in English. I told her that between grown adults of the same general age group, especially in a setting anything short of very high formality, first names were just the way it was. I then went on to explain the more formal situations in which titles could be used, and that for teachers, other adults would only use a title if the person were a doctor or professor. So, from that day onward, she jokingly called me "Professor Wall." (So much for respect!) I appreciated the joke, though; it helped her learn a cultural feature of English-speaking countries.
Respectful forms of address, titles, etc. are much more important here, and many people, young and old, feel they are necessary. People who say learning a language is learning a culture are right; without understanding the culture, you can't get the language 100% right.