Time for a personal anecdote!
Some years ago, I and my folks visited my brother, who currently lives and teaches in Canada, specifically southern Ontario, on the Niagara isthmus. We took the opportunity to skip across the border and visit US in Buffalo, too.
All the American border people looked like surly thugs, but they were uniformly polite, helpful and even friendly; the Canadian border people, when we returned to the Canadian side after a day in Buffalo, were much less pleasant to deal with.
This is obviously a non-representative anecdote, but it has stuck to my mind, since it completely went against my expectations. 
