Middle Management
One of the main themes in this film revolves around Peter's living to work at a company he hates, for a boss that he loathes, but yet still doing everything he asks of him even though his meaningless job takes away from him having any sort of life outside his 9-5 plus weekends schedule. The insanity of this causes Peter to stop being agreeable to his boss, his job and its invisible set of rules that he no longer wishes to live by.
A Better Life
Peter is seeking to have a better life, one where he does what he wants to do when he wants to do it. He speaks his peace to the Bobs in a meeting and is truly unconcerned if he loses his job, he is seeking to completely let go of his so called life and find out what happens. But, in so doing he finds that he is promoted and even championed and rewarded by people for be so carefree. In the end, though, Peter realizes that he still must care for something, to stand for something and to do what is right regardless of everyone else's actions, and this is the only true way to a better life.
Jealousy
This theme permeates through the sub-plot love story between Peter and Joanna. Peter, in determining that he will no longer care about the rules of society then is confronted with the fact that though he doesn't have to abide by them, he wants Joanna to do so. He believes Joanna has slept with his boss, Lumbergh which stirs his jealousy into him realizing that he does care deeply about life and that there are boundaries when crossed cause us to feel out of control. This also causes Peter to reveal that he is jumping to conclusions as the man Joanna slept with was not his boss.
Downsizing
"Downsizing" refers to a corporation's act of diminishing the amount of employees/labor with the intention of saving money. It is frequently used throughout the film and fuels the plot, as it motivates Michael and Samir to create the embezzlement virus. As a theme, its purpose is to exemplify a corporation's willingness to fire loyal employees for the sake of saving a meager amount of money which only assists management.
Time
Time and its relation to the workplace is a recurring theme throughout the film. For example, almost every character is accessorized with a wrist-watch. Additionally, Peter loathes having to work on Saturday and Sunday. Although Peter sleeps through his alarm and doesn't show up on Saturday, Lumbergh leaves him seventeen voicemails, each one conveying the passage of time and how late Peter is.
Arbitrary, nonsensical rules and regulations
There are a number of rules and regulations in the film's workplaces which are objectively imbecile. Peter becomes increasingly annoyed after being repeatedly told to include a cover sheet with his TPS reports. Joanna is constantly harassed by her manager to display more "flair" on her uniform. Milton has his red stapler taken away because personal items are not allowed in the office. Perhaps most nonsensical is Peter's promotion after telling the Bob's how little he works and how much he hates his job.
The film uses these "rules" comedically, although their true purpose is to illustrate the dehumanizing, impersonal effects that work has on one's sense of individuality.
