He definitely had a wry and unique perspective and didn't hesitate to speak his mind, but he could also be quite gregariously social and traveled extensively, engaged in many speaking and lecturing tours in between books, so I kind of doubt it. He doesn't strike me as the type to have suffered from anxiety attacks. He has always been a hero of mine, though. I love his sense of humor. Tom Sawyer and Huck Finn were among my favorite books as a kid, along with Joel Chandler Harris' Tales of Uncle Remus, which are also hilarious (although the idiom in which they're composed makes them rather a challenging read).
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"I don't mean to sound bitter, cynical or cruel - but I am, so that's how it comes out." - Bill Hicks