I am of an age and of a subculture in which authenticity, being honest about who you are, being true etc. are all high ideals. Rachel's post, fits with my cultural assumptions and thus rings true, and Adam's Characteristics of a congregation also sounds to me like the ideal congregation, but....
My extensive "but" has to do with the pastoral office, and the truth that actually will set us free, which isn't our individual truths.
Honesty and authenticity must serve something else. A pastor isn't simply an individual person who gives a sermon on Sunday morning (or in my case evening). A pastor also cares for (shepherds, that is the etymology) the spiritual well being of particular gathered people of God and disciples of Jesus Christ. These gathered people come even in the most homogeneous of groups with differing level's of maturity, differing circumstances of life (much of it stressful or grief ridden.), differing levels of spiritual understanding and experience. A congregation that fits all the characteristics outlined by the introverted Pastor would be a congregation where all the individual members remarkably had such maturity, spiritual and personal, and/or such even keel personal histories as to never have a reactive thought or emotion, or the life experience and wisdom to immediately recognize such reactive thoughts and emotions within moments of experiencing them! On this side of Kingdom come (as some use to say) one will never find such a congregation.
My point is while I am sure many a pastor hides for the sake of the job, and as a disturbingly large number of comments in the comment thread show, congregations can be very petty in their response to any sign of weakness or doubt in their pastor, but honesty and authenticity can be wielded like a weapon, honesty and authenticity can become more important than the Pastoral Office. Honesty and authenticity need to serve the Gospel and the care of souls, and very rarely should be about the pastor.
As a someone who helped start the church I now pastor, and given the make up of my congregation I will admit there is little I feel I need to hide from my congregation. Even so, I am not honest in the ways Rachel Evans enjoins me to be honest. Not because I am hiding but because my opinions aren't supposed to be the point of my pastoral role. They inform what I do, but as Pastor I am to seek to submit my will (and opnions) to the will of God, and to the service of those God has given into my care. I am to lead the people of God entrusted to my spiritual leadership into the fullness of our relationship to God in Jesus Christ,by the power of the Holy Spirit. Sure there are opinions here. But rarely do my doubts serve that purpose. Mainly because my doubts are my own personal struggles with the call of God on my life through the pastoral office. I need a place to take these doubts and struggles, but that isn't the particular congregation, thus one reason why there is the wider body of Christ. The local congregation isn't the be all and end all of Christian community.
Lastly I learned a valuable lesson about the pastor and honesty in my stint as a hospital chaplain in Clinical Pastoral Education (CPE). Sitting with people in crisis in the hospital room recovering or before going into surgery, or when a loved one is in ICU or having just died, honesty about my doubts about the after life, or my theological struggles, or even my struggles with death and frailty only on the rarest of occasions ware comfort or of spiritual help to the patients or their families. Rather, what I was called to was to listen, and based on what I heard in the other to bring my relationship to God, my knowledge of theology and spirituality, my experience in life to bear upon their situation, by reflecting back to them their struggles their doubts, and to affirm that these things are okay, but not by telling them about me, but by being a presence with them in crisis. Most people have friends who can be "honest" with them, what people needed wasn't my personal honesty, but comfort with ambiguity, pain, doubt, death, and life. This I think is a type of honesty, but it is internal and silent, a speaking the truth with out speaking.
The reality is that pastors aren't just Christians who stand up front of the assembly, we are pastors, shepherds of God's people, or we should be. This requires being honest with ourselves, it may mean saying things that may make people uncomfortable, but it also may mean that we never speak to the congregation our deepest darkest doubts and struggles. In my view a congregation should rebel against some form of total honesty. Pastors must tell the truth but the truth their to tell is Christ, not their own individualized truths. According to my tradition I am a minister of the Gospel of Word and Sacrament. The truth I am responsible to proclaim has little to do with my opinions or struggles, but with what God has done and is doing in myself, in the congregation and in the world through Jesus Christ. In that truth telling, I am to follow the example of the one who did not break the bruised read, nor douse the smoldering wick. compassion for ones congregation needs to always be uppermost in a pastors mind. Being honest and telling the truth for a pastor means being acquainted with grief and the pastors own weaknesses not so that she may tell it all, but so she may out of this self acquaintance in love convey Christ to God's people and so that healed and being healed the people of God may being acquainted with Christ know their own weaknesses and in compassion proclaim the Truth Jesus Christ to the world. Due to a variety of realities getting oneself let alone a whole congregation to live fully into these things is a life long task.