Buying & Selling Vehicles across the Canadian - USA Border

Why you have to present the car to the export customs?
In European Community we can cross borders without any taxes, if we sell a car to outside EC the customs are completely desintereted. Only thing you have to declare are military equipments.

And importing is easy, too. All I need is a title with a VIN and the sales-contract. Calculating custom-fees lasts maybe 30 minutes.

I thought trading between US and Canada would be much easier...