Jim and Diane were walking down the road when Billy met them at the end of his driveway. "Come join us" said Jim. And so, Billy joined Jim and Diane and the three of them continued down the road. 

After walking for almost five minutes in complete silence, Billy finally had had enough. "Why isn't anyone saying anything?"

"Well", said Diane, "we weren't sure what to say. I mean, we couldn't continue the conversation we were having before you joined us."

"Yeah", said Jim, "that would spoil the surprise."