Don't let your ego make transactions with insufficient funds.
Basically, do not allow yourself to be so boastful that you cannot back it up. Even if you can back it up, arrogance is a heinous trait. There is a difference between confidence and arrogance. The synopsis of the difference is that one includes acting without being flashy, and the other involves acting flashy. Confidence is not about the flash. Confidence is about showing people you have a glow on the outside because it radiates on the inside. Confidence speaks for itself, so when you enter a room, submit a project, or begin speaking, if you truly have confidence in whatever you are exuding, it will show itself. Arrogance is usually accompanied with insecurities. People who have to make the biggest ruckus upon entering the room about credentials, and accomplishments, especially without being prompted, are often very doubtful of the side of themselves in which they are seeking approval.
Even if you have gained a bit of weight, or do not like your newest hairstyle, maybe even hate the outfit your just bought, if you own it as beauty, no matter what, it will yell to others "I am confident." It is only when compliments get rejected and insecurities are verbalized that anyone can even notice you are not confident. People with large egos have yet to be humbled by their boasting, hence the repetitious claims of things that may or may not exist. Bottom line is, a person who is truly confident will not need an inflated ego because the grandiosity of the accomplishments will not need the bragging.