Dumbledore was a little too dramatic for his own good.

Dumbledore is one of the most enchanting characters in the history of literature. Throughout the series, the man captured our hearts, and we often find ourselves thinking about him as we go about our regular lives. But, as incredible as he was, he did exist in a considerably more dramatic manner than was required.
He viewed the whole scenario with Harry and Voldemort as if it were a play, and he made a point of keeping a lot of things from Harry when he could have easily disclosed them with him.