Prohibited from Entering United States

Hi,

I have been reading a lot about Canadians who are refused entry to the United States for various reasons, i.e. a previous criminal conviction or what not. What is it like to live in Canada, but be prohibited from entering the United States? What type of inconvience does this cause? For some people, the shortest and fastest route between two places in Canada is through the United States. Its one thing to be an American and banned from entering Canada (unless you need to drive to or from Alaska), but it must be another thing altogether to be Canadian, or a Canadian PR, and be prohibited from entering the United States. Anyone have any thoughts, experiences?