For example, my ex-boyfriend always brags about how great he is in everything and how there is nothing he can't do. Everything you named, he swore he could do it and being like he clung so tightly to that belief, his overconfidence led him and I to believe it was TRUE. This led me to overestimate his abilities, as he could do just about anything I name. One thing I can say is that he was good at football, excellent at math, and a hard worker. However, basketball, golf, money management and a few other things I have witnessed his horrible qualities. His confidence level was so high that no matter what you said he couldn't do, he told you he could. However, in some cases, confidence is a good thing when you know what you're talking about; too much confidence can be negative