One of the strangest religious transitions in American history is that the Puritan congregations in New England became Unitarian Universalists. It would be hard to find a religious group who cared more about getting doctrine exactly right than the Puritans, yet within the span of only a few generations, they'd devolved into something unrecognizable as either Puritan or even Christian.
Read the rest of the post to understand how anti-Catholicism, Calvinism, and sola-scriptura-ism leads to not believing in the Trinity or in Hell.
(Remember, even Scarlett O'Hara believed in Hell--she told Rhett Butler she was raised on it! [book or movie? I can't remember].) A Unitarian Universalist church in Wichita exhorts passers-by -- via a sign on their property -- to look inside themselves if they want to find God.
(Image: Cotton Mather.)