Thomas Paine and John Adams fell out after Adams wrote a response to Paine's Common Sense. In 1805 a bitter 71-year-old John Adams wrote to a friend:
"I am willing you should call this the Age of Frivolity as you do, and would not object if you had named it the Age of Folly, Vice, Frenzy, Brutality, Daemons, Buonaparte, Tom Paine, or the Age of the Burning Brand from the Bottomless Pit, or anything but the Age of Reason. I know not whether any man in the world has had more influence on its inhabitants or affairs for the last thirty years than Tom Paine. There can be no severer satyr on the age. For such a mongrel between pig and puppy, begotten by a wild boar on a bitch wolf, never before in any age of the world was suffered by the poltroonery of mankind, to run through such a career of mischief. Call it then the Age of Paine." Thirteen years later, Adams would comment in a letter to Jefferson that Common Sense was "a poor, ignorant, malicious, short-sighted crapulous mass."
Source: Letter from John Adams to A friend, 1805