The Puritans originated as a sect of Protestant Reformers in England who believed that the Church of England was corrupt with Roman Catholic practice. Believing the Anglican Church to be beyond hope for reform, they sought refuge, isolation, and religious freedom in the New World. One of the most famous Puritan communities was that of Salem in the Massachusetts colony. They lived in very strict, religious communities in attempt to purify themselves from the evils of the world.
The Puritans believed in Biblical Absolutism, or that the Bible was the literal word of God and the highest authority. Furthermore, they did not believe in a separation of Church and State. If anything, the Puritans held that the State should adhere to the Church by enforcing laws consistent with Biblical teachings.
The Puritans believed that this world is a constant siege of temptation by the Devil and his demons. It took lots of personal perseverance to remain spiritually pure and overcome worldliness. To minimize temptation by the Devil and emphasize the importance of God, many forms of entertainment or "diversion" were banned. Music was banned from religious services, dancing was considered sinful, theatre and performance were considered a distraction, and even gathering in too large a number was an opportunity for the Devil!
Additionally, the Puritans believed in predestination and covenant theology. This meant that they believed themselves to have been specially chosen by God to live their lifestyle away from the rest of Christianity as truly Godly people.