Oh my gosh, these are sooo funny! I'm from a small town and now go to school in a big city, see I experience all these things every day. Here's some I thought of:
small town: you go to a school where all the teachers are former students who went to college in a small town near by and came back and married other former students that are now teachers.
small town: the parents of your teachers are teachers at your school, too
(both were the case in my high school. soon everyone back home will all be related
)
big city: you have teachers that aren't even from this country