It can be just as insane as a US Citizen traveling to other countries. A couple of years ago, with a comfy severance in the bank, I traveled to Canada to visit a lady I'd become involved with, who had traveled to the US to visit me multiple times.
It was the first time I'd ever traveled not on business, definitely the first time since 9/11 where I didn't clear customs in the company of my coworkers and boss, and it only took a couple of seconds after not answering 'business' as my reason for travel that I realized how insane the opposition people face to just traveling from one country to another as an individual.
I could probably have gotten through the process more quickly, but after spending a couple of hours - during which time I missed my connecting flight and couldn't contact the person waiting at a rural airport for me - I saw a Chinese and an Indian family treated abhorrently, as well as a german student headed to nanny for a family friend for the summer treated with insane harshness.
It was clear the Indian and Chinese families, both of whom seemed to be bringing a matriarch home, had learned to travel as a large unit so that multiple people spoke english and were familiar with Canadian law and so that when they were inevitably held, they would be held together.
The german student seemed a likely victim of a friend trying to talk them up, when the immigration officer called their friend, somehow the story didn't match 100%, and they were told to dig through their email and produce evidence.
When I discussed this with other Canadians during my visit, they said it was very common, and that what the German student experienced could have been as simple as correctly responding that they would not be employed, but would be working for a family friend in exchange for room and board, and the friend may have thought that it made them look better to say, "Oh, of course he will be employed / working!".
Anyway, in my case they found it incredibly suspicious that I had over $10k in my bank account, was not currently employed, and was planning to stay for some weeks. I lectured them on how there are no fucking jobs for me in their country (the younger agent nodded, as if to say, 'no shit), and how it would be kind of absurd for an engineer to illegally immigrate from silicon valley to canada.
Eventually they threatened to deny me entry to the country for smuggling, based on a speck of green plant material they found in the seam of my backpack.
Fucking Hosers, I won't likely return under any circumstances, but I know that's how our EU and Latin American friends feel about the US.
Canadians are particularly nasty at the border. I've found that every time I cross. I keep my information exceedingly short and curt, and keep a confident face on.
Having said that I recently arrived at US border without a printout of my return flight handy. I had to boot up my laptop standing at the immigration desk, which seemed to take forever, which gave the guy plenty of time to wander back through my passport and then start quizzing me on previous trips - arrivals, who I travelled with, departures, airlines, etc. It was extremely taxing to answer these questions accurately, knowing he was probing for an answer that didn't match the records on his screen. Finally the computer loaded, I found my PDF itenary and showed it to him. Everything was in order, but the entire ordeal gave him time to power trip on me, all because I didn't print out the travel itenary and slip it into my bag. I won't make that mistake again.
I've traveled to Vancouver, BC probably averaging at least once a year for the last 16 years -- by car and plane. I've always found Canadian customs to be exceedingly polite and friendly -- to the point of joking around even late in the evening/early morning (on a couple of my road trips). That said, coming back into the US, of the roughly 20 trips, I think the US border agents have been friendly once, polite maybe twice, borderline rude/surly the remainder.
