feif un,
i heard a nice vort from shlomo katz on his cd live in melbourne. He asks, why in between the ashamnus and bagadnus do we sing a tune in major. It would be much more fitting to sing in a minor key.
He answers with a moshul of someone going to court. At first he is trembling, but when he sees that the judge is his father, he rejoices. That is our situation. When we confess our sins, how can we not sing a joyous song, when the judge is our father in heaven.