I am in the business of designing presentations that I hardly ever need to deliver myself. Now and then I come up with this brilliant visualization/analogy that simply does not stick with the client.
First she asks what it means. I explain. "OK". In the next call: "remind how that chart works again?". I follow up with a passionate explanation. During rehearsals: "So, here we have an [um] great example", and the energy in the pitch grinds to a halt.
Time to take the chart out.