What was the most fun part about making an adventure game? And what was the least fun part. And why?

It's hard to say. It isn't clear if it was all fun, or none of it. Building a game is an extremely long, tedious process. On a given day, you don't tend to see much progress. It would be far more exciting to watch paint dry. Probably, the best part is watching someone see, and play the game for the first time. That was always a very cool feeling, when we would blow people away. The worst times were probably the times when we didn't think the game would ever ship, or where the stream of bugs felt endless.