The Canadian guy was a jackass. I cross the border all the time (my wife is American)...
They may ask questions that have nothing to do with anything, the bottom line is... answer them to the best of your ability and be on your way. They ask those questions for many reasons (i.e to read your body language etc. )
American border guards are usually jerks but Canadian border guards are just as bad depending on who you get... they're not there to be friendly.
Personally, I think the U.S. Borders are far more secure than ours on the Canadian side... I've actually driven through to Canada without showing any documentation...
Man who run in front of car get tired.
Man who run behind car get exhausted.