With this discussion of spurious quotes (and I have to think that "denial"
one is spurious for sure), I am reminded of a scene from The Andy Griffith
Show. Andy and Floyd the barber are sitting on a bench outside the
courthouse, sweltering in the heat. (loose paraphrase of scene)

Andy: It sure is hot!
Floyd: "Everybody talks about the weather, but nobody does anything about
it."  You know who said that? Calvin Coolidge.
Andy:  No, Floyd, that was Mark Twain.
[and then Floyd's great line]
Floyd:  Well, what DID Calvin Coolidge say?

[And of course, wasn't it Charles Dudley Warner who said (or wrote) the
weather quotation, often attributed to Twain?]

Right after that, Floyd continues:

Floyd:  "Everybody talks about the weather, but nobody does anything about
it."  Know who said that?  Calvin Coolidge.

So these things are persistent.  But it makes me ask, in the face of all the
false quotes, "Well, what DID Mark Twain say?"

John Bird