In the institution of the Eucharist, understanding is only the first step of the process of salvation, following his example and doing what he did is the next step, which is usually challenging and difficult. In our Christian journey there is a world of difference between talking about love and loving in action, between talking about the most efficient plan of service to others and actually washing others' feet.
Crucifixion was the most disgraceful and shameful of deaths at the time of Jesus. It was reserved for the worst public offenders. So, the cross stood for us as a sign of great shame and humiliation, Can we imagine that we could ever consider to venerate such an instrument of torture and death? It is like to venerate the electric chair! Yet, in spite of of the common understanding of the cross as a symbol of torture and death, all Christians always sang on Good Friday: "Lift high the cross." Could you try to come up with an answer? Why is the cross so powerful in our faith?