When we partake of communion, we may have our special thoughts and ideas that go through our minds. No matter what the details of our theology are, or the particular practice we engage in is, we all do roughly the same thing, partake of bread and wine as Jesus instituted it.
So why do we do it? Jesus clearly explained why we ought to partake of the bread and wine. In Luke 22:19 he said that we do this in remembrance of him.
The word for remembrance in the Greek is άνάμνησις (anamnesis) and is only used in the New Testament 4 times, 3 times to describe the Lord's Supper in Luke 22:19 and 1 Corinthians 11:24-25 and once in Hebrews 10:3 to describe something that the Old Testament people were to hold in remembrance. In Hebrews 10:3 we are told that the sacrifices were a reminder of sin, year after year.
Now isn't THAT a great word study! Do you get it? The Old Testament sacrifices provided Israel with a continual reminder of their sins. The New Testament communion provides you and me with a continual reminder of Jesus, who took away all our sins. Isn't that an absolutely wonderful contrast!