EyeBrock EyeBrock:
US Border Guards are rude dickheads. Never had a good experience with them, ever.
I had one nice guy once out of all the many times I've crossed. It was at Niagara Falls and we were four friends in two cars. Our car passed through a line with a really friendly gentleman as a guard. Our friends passed through the queue beside us and had a serious dickhead.
Other than that, every US customs experience I've had has been unpleasant. Always rude and purposefully intimidating.
On the other hand, I've never had a Canadian guard who was downright rude. Some were not necessarily what I would call amical, but none of them were dickheads and many of them have actually been really nice.