One interesting thing that I learned while I was involved with the Friends Meeting, was that some birthright Quakers (people who are born Quaker) whose families had been Quakers for many generations, still use thee and thou rather than you. I was told by some birthright Quakers who were members of our meeting that Quakers never stopped using the terms because 'you' was originally the more formal term and implied that the one being spoken to was elevated above the speaker in status.