Challenge in D&D

Pen & paper roleplaying games span a large variety of different play styles. But in general they have two main parts: One roleplaying part of interactive storytelling, not unlike improvisational theatre; and one combat part where dice are rolled in some sort of turn-based tactical combat system. Yesterday there was a discussion in the comment section whether playing D&D held any challenge, or whether it was just players sitting around, shooting the breeze. Now as I said different people

World of Warkraft...