To err is human. It is nevertheless difficult for most of us to admit to having erred and to make corrections on our view on the world. However difficult, continuous development is the very essence of learning. The more objectively one learns to observe the facts and one's own assumptions the faster it is to make the corrections.
To approach things more objectively it is useful to reflect past failures and to develop new strategies based on those learnings.
Think about the last time you failed. Is there something that could help you realize this faster if you are faced with a similar situation?
What objective signs your team could use to indicate a need for a change of plans?