They're not! Confidence and unregulated overt vulnerability are conflicting (but not precisely opposite). By acknowledging the possibility that you may have do

They're not! Confidence and unregulated overt vulnerability are conflicting (but not precisely opposite). By acknowledging the possibility that you may have done something wrong, you make yourself vulnerable to judgment, and by doing so confidently you gain respect. Facing judgment is a sign of confidence and it requires making yourself vulnerable. In a more subtle example, showing signs of vulnerability in personal relations is a way of letting others know you, and that takes courage. There'd be no point to having social interactions if you were invulnerable, any interaction would literally be inconsequential for you and thus unmotivated. You "dress up" the vulnerability with a higher level strength (e.g. the capacity to listen to and analyze your own shortcomings), and then it's all good. There's a difference between being vulnerable, and putting yourself in a situation that will hurt you. It's fine to show yourself vulnerable if you can do so in a way that incentives good behavior from your peers.