Here is a wonderful article by the Canadian Homebuilder's Association that explains the permitting process.
Luckily, permits are created to protect you. They protect you from service providers that may take shortcuts to save time. How else can you be really sure that the smoke alarms are in the right place, that there are no buried electrical connections, that the railing on your deck will hold firm, and that your basement won't leak due to poor exterior drainage?
Want to know what happens without permits? Let me introduce you to Mike Holmes, and here he is on getting building permits.