People tend to associate nasal surgery, particularly rhinoplasty, with a certain amount of vanity about the appearance of the nose. While one of the main reasons why people consider rhinoplasty is to improve aesthetics, appearance isn't the only thing that drives people to surgery. Issues with the way a person's nose functions, as well as a congenital deformity or damage that occurred later in life can all play a part when it comes to deciding whether rhinoplasty is an appropriate choice or not.
A deviated septum is simply a septum that leans to one side or other, decreasing the size of the nasal passage in one nostril. The constricted nasal passage can make it difficult to breathe or can lead to facial pain and bleeding from the nose. Not every person with a deviated septum requires surgery to correct it, but surgery is the only way to actually repair the issue. For some people, managing the symptoms caused by the deviation is enough. Some people also don't experience any trouble breathing or have any other issues, even though they have a deviated septum.