The discussion initiated by johnboy about Broken Sword provokes the following question: when is a conversation a puzzle?
Let me put this another way. We all know what to do in an adventure game when faced with a conversation with a game character. Talk to them about everything we can. There often isn't very much to do but sit back and listen.
I am trying to think of situations in which the conversation itself takes on puzzle-like qualities
The best example of what I am thinking about perhaps is in Egypt II, where the conversation choices involve a complicated series of trades with various merchants in order to come up with just the right item(s) at the end.
I think another is in Broken Sword with Kahn on the cliff, though game-stopping dialogue choices are not so much puzzles as just bad choices
Any other examples?