What is most important about the Church’s holy days?

In "God's Word for Today" Gordon Snider writes:

Christianity is a historically based faith, which means that the events of the life of our Lord are important. In the Western Church, we pay particular attention to the birth and death of Jesus, but in the Eastern Church, the calendar has many more holy days that are especially remembered. There is a danger that the Church can become so focused on historical events that Christians lose sight of the contemporary relevance of her holy days. That is why today's lesson focuses upon the significance of the resurrection. Does the resurrection of Jesus Christ have a daily impact on your life? It should! If we have been resurrected with Christ, we will have a new way of living. Philippians 3:10 suggests that the resurrection was not only an event, it is also a present power that is working in our lives. Today Christians rejoice in the fact of the resurrection, but every day should be lived in the power of that same resurrection.

Source: Building Christian Relationships: Adult Teacher's Insights, page 40.