I've been reading bits of this thread on and off, so I apologise if my comments cover already trammelled ground...
But I thought I would reply as a (learning) Catholic to Fea's original question.
I was raised Catholic, drifted away for a bit, dabbled in Pantheism, Dualism and so on (C.S. Lewis put paid to the Dualism, I may add
). I thought, why should I need a priest to connect to God? Why should I go to Mass? How can a priest be a mediator, how can he have powers that the ordinary lay person does not? How can he transubstantiate the host and take away a person's sins? Why should I believe all these weird doctrines anyway? And isn't organised religion a Really Really
Really Bad Thing () as well? *I* don't need it - surely I can worship God in my own way. (If I am being honest, all of this was underlined by self-congratulatory thoughts of 'I'm far too clever and liberal to accept the fusty old teachings of a bunch of homophobic weirdos in the Vatican' and 'Now I don't have to get up at 10am on Sunday! Yippee!' And so on.)
I went back to being a praticising Catholic a few months ago because I now think that my limited experience and knowledge cannot measure against the collected wisdom and experience of the Church. I believe that the priest acts as a mediator, an intercessor, that he is granted the power to forgive. The reason I believe this has already been articulated by Rusmeister:
"Asking God for wisdom does not guarantee His granting it, any more than anything else good and virtuous we may ask for. Therefore, when you come up with an answer in a question you are seeking wisdom on, do you hear a voice outside of your self, or within your self providing the answer you come up with?
It may be that God has provided a Church to provide a lot of the answers and wisdom you seek. You are quite right that the Church is made up of sinful humans, but what is the point of It if we can't trust It in spite of It being an establishment of Christ Himself? Where can we know that there is grace to overcome the sinfulness of man and provide any true answers? Why would you place less faith in It than in yourself to seek wisdom?"
So, I trust the Church's authority on this - not blindly or unthinkingly, but because I now think the Church knows a great deal more than I do. And (for me) it feels rights, it works