Nazi like? You mean they herd up entire groups of people by race and send them off to concentration camps?
Hardly.
I have fairly extensive experience with all four different border US/Can border crossings in Michigan and have never once been harassed in the least. Even though it's a little further away from me, I usually prefer the Blue Water bridge in Port Huron, as it's typically got the least traffic. I can see "Matty" Moroun's Ambassador Bridge from my house on a clear night, but it's usually quite crowded. The tunnel is a little quicker, but it creeps my wife out traveling under the Detroit River.
I've only used the Sault Ste. Marie border about three times for various fishing trips, but it's been fine, as well.
The encounter always goes about the same. Pull your car into a booth line as the traffic widens out after crossing, make sure you pick an appropriate line for your vehicle type (they're clearly marked). Wait behind the scanning zone stripe until the previous car clears the booth (again, this is clearly marked). When the light or gate indicates it's clear, proceed through the scanning zone to the booth. Roll your window down, talk with the guard for a minute. Just answer the questions politely and honestly. Don't be sarcastic or annoying. These guys have had a long day baking in their little booth while dealing with smart asses. Remember, they're really just peons that have to go through a checklist. They're not the ones that set the policy. Help them get through their checklist with a minimum of fuss. Drive through when they tell you to. Remember speed limits are now in Metric, so don't get all excited when you see that "Speed Limit 100" sign as you're re-entering the freeway. Congratulations, you're now in a foreign country.
And, as for the guards attitudes, themselves, the US guys as you're coming back into the US are a lot worse than the Canadians. The only couple "Super Troopers" attitude guys I've seen have all been on the US side. Never had a problem from them, just following common sense courtesy, though. My wife got harassed a bit by a US guard after buying a pair of gloves in Canada and forgetting to declare them when coming back. Of course, I wasn't with her in the car at the time, so I'm not exactly sure what transpired before that point. My wife has a little problem with her sarcasm tone at times.
And even then, she still got through the border in under 5 minutes, got to keep the gloves, and just got a warning and glare.
Come to think of it, I've never had a problem calling customs directly, either. Canadian waters are a few seconds away from my house. The only time you need to call Canadian customs is if you plan on anchoring or going ashore in Canada, though. And, if you do, you call them before setting off, give times, boat registration number, etc, and you should be all set. You don't need to talk to the US before re-entering in that case. I don't think Canadian customs allow calls from cell phones, though, so that is kind of inconvenient. We don't dock or drop anchor in Canadian waters too often, so I kind of forget. Occasionally while out on the open waters, an OPP (Ontario Provincial Police) boat will pull up for a safety inspection. Really, they just want to see basic equipment (fire extinguisher, throwable life ring or cushion, life jackets, horn) and make sure you're not completely drunk while operating the watercraft. Simple, obvious stuff.
You really don't need to fear traveling. Just use a little common sense and common courtesy. (Of course, both of those are getting rather rare in the US these days...)
