Our shared border is just weird. I've ordered lots of stuff from Canada, it always arrives with no trouble, undisturbed. I've sent stuff there, takes forever, seldom arrives unopened.
When I go to Winnipeg, I never have any trouble getting through, but I almost always get hassled by a US customs agent comming back.
There is a rest stop near Drayton, ND on I-29, ~45 mi south of the border. It is not unusual to see the trash cans bursting with clothing tags, labels and other signs of recent purchase, but only on the northbound side.
Every winter a couple of snowmobilers get mixed up and get arrested for illegally crossing the border, doesnt' matter which side you're from.
Water rights, and drainage issues become international incidents, a super-duper bureaucratic headache.
We go there for Lasik eye surgery, they come here for cosmetic surgery.