The hosts were particularly happy about Jack's dry wit, since it gave them a new topic to talk about after the conversation had dried up. Well, for them anyway. Daniel could have talked forever about the importance of not only the absence of words, but the importance of the specific places of the invisible words.
Jack however could only stand for a limited amount of silence before he needed something for his dry throat. Their hosts apparently agreed, and the conversation moved on to how invisible water glasses were perfect for holding invisible water and other invisible drinks. Daniel was visibly unhappy.