From reading about the American revolution, it was as much as civil war as a war with England. There were huge numbers of colonists who opposed independence, and a lot of them ended up as refugees in Canada. The Loyalist crew were a fierce bunch, both within the country and outside it. They cared a lot more than the British did, and they moved north with a great hatred of their neighbours. They were the original English speaking Canadian population, although waves of immigration since have made them less significant. From documents at the time, the British seemed to view the loss of the American colonies as predictable, if avoidable. For a while, they thought there'd be a counter-revolution and that they'd be back. . Since the English revolution and the restoration of the old order, a lot of the British rebels had gone to the Puritan regions of the future States, and they and the culture they'd contributed to were a thorn in their side. The 13 colonies had provided cover and support for men wanted for the killing of the king, and English religious politics were a thing in the future US. I think the Brits thought the revolutionaries would turn on themselves, and they'd pick up the pieces.
I recently read a biography of Benedict Arnold, to try to understand why he changed sides, then changed sides, then changed sides. There was a lot of it about, and he found it hard to represent the revolution in regions where it was no longer popular. He was a social climber, and was bought by wealthy Americans (not by the British) who opposed the rabble following Washington. It really was a civil war going on, pretty well like in every colony everywhere that fought out from under an empire.
When it didn't happen, the US became just another nation. After the north south war, when the US finally turned on itself but too late for the British to profit, they established Canada as they knew that without slavery, the US was going to grow very fast and become very aggressive, and they wanted to steer them away from the resources to the north.
From what I can see from travels and from the Brit expat community - no hard feelings about losing the land and people view the US as any people in any time have viewed powerful empires.
I figure this isn't politics because it's historical.