I am thinking along the lines of driving in your car.
The only border I’ve driven across has been Canada/US. Basically, the border guard asked where I’m from, where I was going and for how long I’d be there. Thats it, and I entered the US. No ID shown, no fingerprints, no passport, nada.
How about say, Germany to Poland? Italy to Switzerland? Egypt to Libya? (Just as examples, if you don’t know about Egypt/Libya, don’t worry about it!)
Well, I can give you two examples. Sweden to Norway and Germany to Holland, in both cases there was a sign on the roadside announcing that, well, we were in a different country now (gives you a good idea of how germans drive when there was signs in german on the dutch side telling us to mind the speed limits :)). No customs or guards to be seen anywhere, it seems that some parts of this EU-thing is working as it should. 
Much of Europe is essentially borderless because of the European Union. Switzerland, ever the iconoclast, still maintains borders. Upon entering Switzerland from Italy, you are required to display on your auto a special sticker. If you don’t already have one, the guard will sell one to you. So, basically, there is a cover charge to get into Switzerland.
Moving from Italy to Austria or Austria to Germany, etc., is as uneventful as travelling from here to the corner.
I’ve crossed from Syria to Lebanon. Depending on your nationality, you can just buy a visa get it stamped into pasport and drive (or be driven in my case) through.
Poland to Slovakia is just show passport, get stamp and pedal on by. I believe it was the same in a car.
East Berlin to West Berlin used to be fun. IIRC you could walk across (with passport) but you were forced to change a certain amount of foreign currency at the checkpoint. The Ostmark could only be spent in East Berlin, of course.
However, when I entered Switzerland from France on the TGV train last July, there was no ID check of any kind.
There is a document check travelling between Panama and Costa Rica. Between Panama and Colombia, there are no roads. If you walk across the border, and manage to avoid the guerrillas, you are supposed to check in with the police at the first town you come to (if it has a police post).
I think that sticker you were sold when entering Switzerland was a fixed charge , or toll, for using the motorways ( freeways ) . If you do not intend driving on that sort of road you do not need the sticker. As for crossing other borders in Europe you just do not notice when you have done it as there are no controls or border check-points. Some people in Europe live in one country and work in another , commuting between the two every day.