A powerful idea communicates some of its power to the man who contradicts it. Partaking of the universal community of minds, it infiltrates, grafts itself on to, the mind of him who it refutes, among other contiguous ideas, with the aid of which, counter-attacking, he complements and corrects it; so that the final verdict is always to some extent the work of both parties to a discussion.
A leader has to be positive about all things that happen to his team. Look at nothing in the past as failure.