Writing software requires a level of detail and perfection that no human can reach. We should dedicate ourselves to constant improvement, not perfection. When an error is detected in your code either by you or by others, discuss it openly. Instead of castigating yourself, use it as a learning experience for yourself and others.
Reference:
Gerhart, S., and Yelowitz, L., "Observations of Fallibility in Applications of Modern Programming Methodologies," IEEE Transactions on Software Engineering, Sept 1976.
