I've never had any problems crossing the border in either direction. I don't try to be evasive or overly chatty - just pleasant, polite, direct and honest.
I've dealt with Americans for decades (selling to them & buying from them). Again, for the most part they're the same as us. On recent trips, most of the people I've run into say things like, "He won the election, he's the president and I will respect the office; but jeez I'll be glad when he's gone."
Yes, from time-to-time you will run into a 'Mericun, complete with his/her guns+jesus+constitution= USA!USA!USA!, but not that often.
Fear, mixed with desperation and anxiety over social and societal change that you can't control creates the Trumps and Sanders of the political world.
It is also possible to run into the smug Canadian up here, and also when one travels abroad. He/she freely and without prompting extols all the superior virtues of Canada & Canadians. A few years ago in Nepal I struck up a conversation with a fellow in a tea lodge on the trail to Everest base camp. After a while he asked where I was from, and learning I was from Canada he said he was surprised as I didn't have a flag on my pack so people didn't mistake me for American (he was American). I told that my perspective was if someone plodding along this trail, in this spectacular place, surrounded by this culture was going to judge me (one way or another) based on a flag sewn to my pack then I'd rather they just leave me alone.
As for boycotting US products, I try to purchase Canadian grown/made wherever possible but if the choice is made in USA or Europe vs. made in China for example I'll buy the American or European one - all things being more or less equal.