Why Such and Exclusive Feast? (1 Corinthians 10:14-22; 11:28, 29 (LD 30)

When we look at the Lord’s Supper we might think that this is something that is empty or something that we do on Sunday.  Our concern is that this is something that could just be a mere sentimental memory of Christ rather than communing with Christ.  How do we know that this supper is more than that?  How do we see that this supper challenges us to live in an exclusive relationship with the Lord?