From what I can gather the sitation goes something like this.
Most Americans don’t really hate Canada at all. I am sure there is plenty of resentment b/c canada frequently disagrees with american policy (softwood lumber, iraq, fish, oil, immigration, terrorism, borders etc).
There is actually a pretty serious anti-american sentiment amongst canadians and canadian politicians. Quite a few canadian politicians have been caught talking smack about the US and its government. From what I can tell there are a few reasons for the anti-americanism in canada.
Anger: Many canadians are just angry with the american government. The power difference b/w the two countries means that the US can, and does, simply back out of deals and ignore NAFTA ruilings (softwood lumber particularly). Many also find US foreign policy to be ethically wrong, racist, oppressive, illegal etc (canada isn’t much better but our crimes are far better hidden).
Envy: I am pretty sure that, on at least some level, canadians are jealous of americans. I don’t think this jealousy has much to do with money/power. I do think the jealousy is about culture. Canadian culture is weak, dispersed, and very hard to define. The US is overrun with symbols of national identity and canadians (exempting first nations and people from quebec) really have very little along those lines. Canadians spend all their time watching american tv and usually know more about american politics than they do canadian. So they make stupid beer commercials that place the canadian sense of self as being “not american”. Understandably that envy frequently manifests as resentment.
lasty (sorry this is so long) there is…
Fear: I think a fear of america is the biggest cause of anti-american sentiment in canada (especially amongst politicans and the politically aware). The US has a population, economy, and military that all vastly outstrip their canadian equivilents. Someone mentioned earlier the idea of manifest destiny and I do think that is a very important point. When the american government (ANY administration) decides it requires something (land, water, oil, timber, saftey, power) to maintain the “American Way of Life” little will stop them from obtaining it. What we will see in the next couple decades is that sense of Right manifesting itself on the Canadian people. As china moves to control middle eastern oil the US will come to rely more heavily on canadian sources (tar sands particularly) and if canada stops putting out…there will be big trouble. Global warming will cause similar issues with water (many US aquifers will be dry in a decade or two). One way or another Canada’s sovereignty will be comprimised by american resource demand, its inevitable if the US wants be at all competetive with China.
Sorry that turned out much longer than I had anticipated. I really do think those things are the source of anti-americanism in canada. I am not necessarily saying I agree with them, that is just how things are perceived this side of the border.
disclaimer This is NOT a universal stance in Canada. Many canadians don’t give a crap about the US or are quite fond of it. There are even a chunk of Canadians who want the US to annex Canada.