Anybody who has had a chance to walk through an oil refinery would probably marvel at the enormous size and complexity of the project. Put it simply, it's a bloody miracle that it works!
The sheer size alone would put even the most trusting in doubt that something useful would come out of the taps at the 'other end'. From the perspective of an engineer, or anybody who understands the processes involved, it's really just a series of smaller processes all attached to each other with the same goal in mind - produce various refined products from their raw source - oil.
We had an opportunity to spend some time at two different refineries - one in Sarnia, and the other in Denver. Both were unique in their own way, and similar in size - enormous!