Trust is difficult to gain and easy to lose. If someone betrays you profoundly, that betrayal will tend to crowd out and overwhelm all that came before it. This is true of people and nations.
Canada and the United States have been friends and allies for many decades. Our troops fought together, bled together, and died together in global conflicts, and many aspects of our culture have long been deeply intertwined. Canadians consume significant amounts of American entertainment, and many Canadian entertainers achieve high-level success in the United States.