As a Protestant, I always knew the significance of Easter. However, until I became Catholic, I never fully appreciated it the way I do now. I love Easter and I love Holy Week. It's the most beautiful and profound time of year for me as a Christian. As a Protestant, I never acknowledged Palm Sunday, Holy Thursday, Good Friday, or Holy Saturday... all which are crucial days of reverence (along with Lent - the 40 days prior to Easter devoted to fasting, abstinence, and penitence) in preparation for Easter. I feel like I missed-out all those years (without knowing it at the time), on truly soaking into my heart, all that the Easter message and Christ's Passion was meant for me.
There are many celebrations in Catholicism that are Traditions. Other Christian faiths don't understand why we practice our Traditions, and I'm sure that includes Ash Wednesday, Lent, and Holy Week. As Catholics, we're taught and believe that God's Word is not only given to us in Scripture alone, but also through Holy Tradition. The early Christians did not have the New Testament. It was the apostles that passed down Jesus' teachings through hearsay, example, and traditions. (I plan to explain how this is true in more detail in the future.) Here's what they teach about Tradition in the new Vatican Catechism of the Catholic Church* - (numbers are paragraph numbers)
#81 "Sacred Scripture is the speech of God as it is put down in writing under the breath of the Holy Spirit." And [Holy] Tradition transmits in its entirety the Word of God which has been entrusted to the apostles by Christ the Lord and the Holy Spirit. It transmits it to the successors of the apostles so that, enlightened by the Spirit of truth, they may faithfully preserve, expound, and spread it abroad by their preaching.
#82 As a result the Church, to whom the transmission and interpretation of Revelation is entrusted, "does not derive her certainty about all revealed truths from the Holy Scriptures alone. Both Scripture and Tradition must be accepted and honored with equal sentiments of devotion and reverence."
#83 The Tradition here in question comes from the apostles and hands on what they received from Jesus' teaching and example and what they learned from the Holy Spirit. The first generation of Christians did not yet have a written New Testament, and the New Testament itself demonstrates the process of living Tradition.