People often try to impress their friends online, but we don't know how well they do it or what they talk about to try to make themselves look good. In the face of known egocentric biases, which cause communicators to overestimate the extent that audiences will understand the intent of their messages, and self-enhancement biases, that cause people to overvalue their own behavior, it is likely that many self-presentation attempts will often fail. However, we don't know which topics cause such failure. In an empirical study, 1300 Facebook users evaluated their most recent status update in terms of how good it make them look. In addition external judges also evaluated the same update. Posters and outsiders agreed only modestly about how good an update made the poster appear (r=.36, p<.001). Posters generally thought that their posts make them look better than did the outsider judges. They also disagreed on which topics made them look good. Posters were especially likely to overestimate their self-presentation when they wrote about the mundane details of their daily life (e.g., Clothing, Sleep, or Religious imagery), but underestimated it when they wrote about family and relationships (e.g., Birthday, Father's Day, Love).