When watching a film, you hope the makers respect you. You hope that the director, producers, actors and all other members of the crew have enough decency to tug you along for a ride and, when finished, it has all made some kind of sense.
Ultimately, if the writers behind the film manage to lose you in the world of the film, you may be satisfied or, in fact, pleased when the film comes to its ending. However, if it failed to connect all the details, if it didn't explain enough, or if there are major inconsistencies within the film especially the world it created, then you probably will not like the film. You probably will go home unhappy that you spent about two hours in a movie theatre.
For Christopher Nolan's film, Inception, this is also the case.But, unlike many films, he succeeds.
Nolan builds up a set of "scientific laws," which if the viewer can comprehend he or she will see play out consistently throughout the film. He creates a profession known as extraction that does not exist yet, which involves being paid to raid people's minds and extract information usually on behalf of very powerful people in the world who are tied to huge corporations.
Cobb (Leonardo DiCaprio) is the main extractor in the film. He has a right-hand man, Arthur (Joseph Gordon-Levitt), who helps him coordinate extractions. Cobb assembles crews for each extraction and the way an extraction works involves finding time when the subject with the idea can be put into a "dream state" with a device that hooks up the crew conducting the extraction to the subject who has the idea that needs to be extracted.