I was raised Quaker, and in theory one of the core tenets of Quakerism is that uncomfortable honesty. Trivial example: refusing to swear on the Bible because that would imply that you might not be honest when you hadn't just sworn on a Bible.

I have found that Quakers are just as fallible as anyone else; but the subset of Quakers who really live that tenet have an unnerving and extremely peaceful unflinching willingness to comment or question on problems in a way that removes the smokescreens of social obligations. I've found it far easier to talk about anything involving money, feelings, sex, danger, beliefs, crime, fear, etc. with those individuals who have really committed their lives to only let truth come out of their mouth (even if they don't always succeed).