It's very important that you don't mistake confidence for arrogance. Arrogance is nothing more than insecurity in disguise, and most people can spot the difference between the two. An arrogant man is the one who brags about what he can do. A confident man shows others what he can do. Arrogance is bragging about your abilities.
Confidence is an attitude that comes from being prepared.
Prison inmates have been the subjects of many crime-related studies over the years in an attempt to learn how they choose their victims. In nearly every study, the results came back the same. The majority of convicts interviewed claim they always made it a rule to choose someone who looked unprepared, unaware, insecure, and easily intimidated. Furthermore, the prisoners maintained that they could accurately size someone up in all four of these categories with one simple look-over. Like bad cologne, everyone knows when you're wearing confidence.