Lord Jim takes place in the late 19th century, and those Victorian Brits weren't exactly known for being chill and flexible. When Jim disobeys the social code that governs his group of "gentlemen" sailors, he has to be punished as a result. His most significant punishment comes in the form of a major blow to his reputation, which he attempts to avoid and then rebuild over the course of the novel. The problem is, when it comes to his reputation, Jim is his own worst enemy. By refusing to let the past go and move on, he practically forces people into judging him unfavorably, and his inability to get over his mistake ensures that his past will haunt him for the rest of his life.
In Lord Jim, having a good reputation is basically meaningless. Brierly, for example, shows that your inner emotions matter far more than what people think of you.
Jim is obsessed with regaining his good name, yet his obsession with the past causes him to damage his reputation even further.