Sticking It to the Man
The main theme of the movie - and also the answer to its appeal - is that high school kids get the better of the adults who are in authority, but it is also appealing to anyone who has ever felt like they are unable to get the better of those who are in charge of them. Sticking it to the man is the main theme of the movie. Ferris is perennially annoying and constantly proud of his own cleverness, but nevertheless, he is almost an adult who still needs a note from his parents to validate a cold. From a teen perspective this is an incredibly frustrating state of affairs, and this theme appeals to a teen audience who feel that many school rules are in place purely to make them obey rules, and who sometimes feel that their teachers have forgotten what being a high schooler felt like.
However, adult audiences want to stick it to the man as well and for this reason the film also transcended the usual teen flick genre. Bullied by your boss? Want to take that sick day to go to your kids' sports day but you're line manager won't let you? Want the breakfast item on the menu at 11:01am and the restaurant won't serve it to you? For anyone who has ever been aggravated or aggrieved by petty rules that they are powerless to change, this is the perfect movie because of its central theme of beating the authority figure, and not just beating them - sticking it to them, and coming out on top.
Sibling Rivalry
One of the lesser themes of the movie is that of sibling rivalry. Jeanie, Ferris' younger sister, is almost as put out about the success of Ferris' high jinks as their school principal is. She is deeply irked that Ferris gets away with all sorts of lies, schemes and shenanigans that she knows perfectly well she would never get away with; for example, when she comes home to find a disheveled and muddy Mr Rooney in her front yard, she understandably kicks and attacks him, and of course he makes a speedy getaway, leading the police to believe that she has made a prank call, and getting her into trouble. It is a constant source of annoyance to her that she does the right thing and gets intro trouble due to a misunderstanding whilst her brother never does the right thing and is given the benefit of the doubt every time. There is such a strong sense of sibling rivalry throughout the movie that it is almost an unexpected plot twist when she switches sides and starts respecting Ferris for the way in which he beats the system.
Abusive Parents
Because the movie is a comedy, and also very fast paced, the theme of violence in the home is almost under the radar; the gloomy outlook of Cameron is semi-comical, but its underlying reason is a childhood spent frightened of an abusive father with extreme anger issues. When Cameron's father's Ferrari is wrecked, Ferris offers to take the blame himself because he knows that Cameron will be punished very hard by his father; however, Cameron has also realized that the reason he suffers from low self esteem and does not respect himself is that he has yet to stand up to his father; the incident with the car is his epiphany and he decides there and then to make this the day he stands up for himself.
Living in the Moment
Ferris, Sloane, and Cameron have built a lifetime of memories and care deeply about each other, but they are also refreshingly realistic and they know that their relationship is about to change. They are all headed to different colleges after graduation, and they will not be able to live such a responsibility-free life anymore. This is why they live in the moment as much as they can now. They don't want to remember their youth as spent in boring classes; they want to enjoy the beautiful weather, explore the city, and appreciate their youth for what it is. There is a saying that "youth is wasted on the young" but Ferris, Sloan and Cameron actually disprove this.
