G.K. Chesterton infuriated some Americans back in 1930 when he said, while visiting New York on Thanksgiving Day, that the English should institute their own special Thanksgiving Day—to celebrate that the Pilgrim Fathers had left. No wonder he felt that way. Consider The Oxford Dictionary of the Christian Church’s description of Puritanism: “They demanded express scriptural warrant for all the details of public worship. They attacked church ornaments, vestments, surplices, organs, the sign of the cross.” Eric Voegelin considered the Puritans one of the earliest strains of modern gnosticism and described (borrowing from Richard Hooker's Ecclesiastical Polity) in great detail their use of social boycotts and political defamation in their campaign of intolerance toward other Christian denominations and the study of classic philosophy and scholastic theology. Voegelin said their attack against the Western tradition was so effective that Western society has never completely recovered from the their blow.
But I'm still happy they came.