In a February 6, 1862 letter to his brother Orion, Twain described a visit to a fortune-teller, in which he quotes her as saying many things about his brother (Orion), such as, "..he is too visionary--is always flying off on a new hobby; this will never do--tell him I said so." &c

To me, it's pretty obvious that Twain is pulling Orion's leg, or trying to counsel him, by relating this "conversation."
The editor of Twain's letters, though, seems to take Twain's account as "gospel," though, writing:
"It is not so difficult to credit Madame Caprell with clairvoyant powers when one has read the letters of Samuel Clemens up to this point."
My reaction is, "What!?! Don't you know Twain was a kidder from the cradle and remained one all his life? And that he would not miss an opportunity to tease his brother thus?"
What do y'all think?
- B. Clay Shannon