Human and Divine
I have always known about the two natures of Christ. I learned in catechism class that Jesus is full God and fully man. Not half God and half man but totally and completely God and totally and completely man. Something that does not seem possible but that is what scripture says. That is an interesting teaching but why is it important? Well, you can see certain heresies coming from focusing too much on the divinity of Christ or too much on the humanity of Christ. But really this idea was just something you learned and maybe even taught but it was not all that practical.
As a Catholic that all changes. The idea of the church as the body of Christ becomes much more real. So Jesus being human and divine implies that the church is both human and divine. That brings it a lot closer to home.
There is an article that suggest Vatican II was about bringing that balance back to the church. That because the church was reacting to the protestant idea that the church is not divine it had drifted into triumphalism and was neglecting the human nature of the church. Of course, when the course is corrected some people will drift off to the other extreme. So you have some who are overly critical of the church.
The truth is Vatican II was a call for renewal. That means that you need to be honest about your weaknesses so you can see the need for renewal. It also means you must be honest about what is true. Without truth you have no goal for renewal. The key here is the church does not look to any other institution to find that truth. She has it in herself. That is because she is inherently divine. So Vatican I is in some way a prerequisite to Vatican II. Before we can renew the church we need to know what old things should never be made new. Some old things are good and need to be preserved.
This is really the problem of truth. We cannot always think progressively because some truth actually lies behind us as revelation from God. We cannot always think conservatively because some things that are old are not good. Most of us are naturally progressive or naturally conservative. So as a community we have a good balance. But we have a tendency to see each other as enemies rather than as complementary gifts to the church.