We often assume the Lord expects us to be perfect today, when He has never asked that of us. (Yes, I've read the Sermon on the Mount)

We are like students coming into a classroom thinking the teacher, who we love dearly, expects us to already know everything she is going to teach that year. Of course no teacher has that expectation.

God, like a great teacher, does not expect all-knowing perfection, but instead expects us to listen, to be respectful, to make a real effort to learn from our mistakes, and to be nice to the other students.