Why are sacraments so important to Catholics? They bring God's grace to us in a very real and physical way. They were given to us by Jesus Christ and as such we consider them essential for salvation. Grace is like water to us Christians; we need it to survive spiritually. Grace is the spiritual "electricity" that makes us holy and keeps us holy. It is God's gift to us, freely given in his infinite love. Our participation in the sacraments provides is a means of devotion and acknowledgement of receiving these graces at the proper times in our life.
Some sacraments are necessary only once in life, others as required or even as frequently as we feel necessary. But all come with the gift of grace in some special way. Our willingness and effort to participate in these sacraments tell the Lord that we are ready and willing to do His will to the best of our ability and desire to receive His gifts to do it.
No other Catholic activity is so personal, yet public, inspiring and strengthening, than receiving the sacraments.