Later on in the movie, Cobb searches for a new architect to construct the sets of the dreams he will be entering. When he finds Ariadne (Page), he soon teachers her how to completely build the world of your dreams from the ground up. This shows the psychological principle that you can construct your own dreams. Although it is elaborated in the movie, it still conveys the message that you can create anything at all in your own dreams.
Finally, something that keeps reoccurring throughout this entire movie is the presence of Cobb’s wife, Mal. She appears in every one of Cobb’s dreams and soon makes her way into other people’s dreams through Cobb’s subconscious. This shows the psychological principle that bad memories can haunt your dreams. Cobb has a very bad memory of his wife committing suicide. Since he has not properly dealt with this pain, she creeps her way into his mind and truly haunts him until he ends it.