I cleared Canadian Customs last summer and the guy was very professional and polite. When I cleared American Customs I had the same experience.
I had a different experience. Canadian customs troll-witch intentionally slowed down my process so that I missed a connecting flight in Toronto.
As to US Customs types, I once literally dragged one royal a-hole into his supervisor’s office and forced him to apologize to some German friends of mine. I was hopping mad at how he treated my friends for absolutely no reason.