Nobody likes a show-off. Why do you think people always root for the underdog? Having faith in your abilities and exuding confidence are necessary for success, but boasting is definitely not okay. Show humility when you make a mistake. When you acknowledge what you did wrong, people will be both surprised and impressed with your honesty. Pretending to be infallible will only make you look unprofessional and unreliable. There is an immense amount of value in honesty and humility. People trust in those who are sincere. Not to mention, when you learn from your mistakes, you can communicate those experiences and offer perspectives to others. So make sure you are being an honest businessperson. Others will see that in you, and your credibility will increase.