From what I've been reading on social media, Canadians are fine about US citizens visiting, so long as you don't loudly support DJT and his policies, 'joke' about the 51st state and generally act totally cluelessly about the sovereign nation to the north of you.
I haven't lived in Canada for a long time, so I can't guarantee, but I'm sure the Maritimes would be happy to get your tourist dollars too.
Certain cruise destinations in the Mediterranean are absolutely over-run with tourists and the locals are getting a bit ticked off, apparently, tho that's not against US citizens in particular. Canada's a great place to visit!
MOO