THE SINGLE BIGGEST PROBLEM WITH QUOTATIONS IS THE ILLUSION THAT THEY HAVE EVER BEEN SAID

Richard Dietrich, treasurer and webmaster of the ISS, wanted to know if the following quotation was Shaw's: 

"the single biggest problem with communication is the illusion that it has taken place"

Well, so far my database says that these words were never uttered by Bernard Shaw, although one can never be absolutely sure about these things. Better-informed opinions are welcome. 

However, I've found a few items that make this quotation even less plausible, regardless of the accuracy and scope of my search. 

• Two of the few people (on the web) who claim to source this quotation in a published book, indicate the preface to The Doctor's Dilemma as the source. Nothing close to the above sentence can be found in the preface or the play. This bold (and false) reference is from 245 of The Rabbi and the CEO: The Ten Commandments for 21st Century Leaders.
• This dictum is quoted elsewhere in a number of slightly altered versions, especially of the second half of the sentence. Among these are "the illusion that it has occurred" or "the illusion that it has been achieved."
• The quotation is also attributed to a number of prominent figures, among whom Albert Einstein is often mentioned. On page 194 of Effective Opportunity Management for Projects: Exploiting Positive Risk, for example, you'll see one of the many Einstenian attributions. 

As usual, whenever one makes one of these searches even a seeming failure has a silver lining. On this occasion, I found a curious critical comment in Archibald Henderson's Bernard Shaw: A Critical Biography (1911) when I started looking for the individual words of the quotation after an "exact match" query would not return any results.

"Again, Shaw goes to the length of explaining dubious and laconic remarks of his characters, thus totally destroying the realistic illusion that this conversation is actually taking place." And a few lines later he goes on to say that "With all Shaw's praiseworthy efforts to create the realistic illusion of life by making us forget that his characters are only fictions of the stage, he occasionally destroys that illusion by making us remember that they are only the puppets of Bernard Shaw." (p.414-15)

What do you think? Same old, same old.