I am making a complicated point, telling a joke, or relating a story that illustrates some new idea. It's hard to get across, and after I make my point or tell my story, the other person doesn't seem to get it. Finally, my conversational partner brightens up and fully comprehends the big idea. Then, he or she informs me happily of the complicated point or the reason for hilarity or the moral of the story, in a thoughtful but triumphant way. Clearly I hadn't thought this quite through, but my story does lead to an interesting spot, had I only seen it!
It makes me want to kill people, with a shovel.