Catholics honor Mary because God has honored her. God has given Mary the highest honor that is possible for a human person. Are we speaking of the honor that God bestowed on her when he took human nature from her flesh and dwelt in her womb? Actually, no. There's another reason why Catholics honor Mary. Do you remember in the Gospel of Luke , when a woman cried out to Jesus, "Blessed is the womb that bore you, and the breasts that you sucked!" Jesus replied - "Blessed rather are those who hear the word of God and keep it." (Luke 11:27-28)
We honor Mary above all because of her faith and total submission to God's will and plan. When the angel Gabriel appeared to her and announced that she was to be the mother of "the Son of the Most High," who would inherit the throne of King David and rule forever, Mary did not doubt, even though she was a virgin. She replied, "I am the handmaid of the Lord; let it be to me according to your word" (Luke 1:38). For this response of total faith, the Holy Spirit inspired her cousin Elizabeth to tell Mary, "Blessed is she who believed that there would be a fulfillment of what was spoken to her from the Lord" (Luke 1:45). The Lord honors Mary because she, above all people, heard the Word of God and kept it.
After her cousin Elizabeth had praised her, Mary in turn directed all the praise and glory to God: "My soul magnifies the Lord, and my spirit rejoices in God my Savior, . . . for he who is mighty has done great things for me, and holy is his name" (Luke 1:46-49). This great hymn of praise to God, Mary's Magnificat, expresses perfectly her heart and her attitude.
Catholics see Mary as one of God's greatest gifts to the Church. Mary is a model for all Christians. Mary lived her whole life in perfect obedience to God, by faith in God, wholeheartedly responding to God's grace and call. She is a model of discipleship (following Jesus), a model of faith and a model of the Church, expressing all that God calls the Church to be and to do.