Despite their lack of reverence for the meal and their lack of sensitivity to his comment about being betrayed, Jesus did not use the occasion to chastise his disciples. Rather, he seized the opportunity to teach them about kingdom greatness. Until then, the lowly path of servanthood similar to the example of Jesus would be expected of them. At issue here is a person's appraisal of worth. Our world teaches that our value lies in proportion to our power, i.e., how many people or resources we can control.
Greatness seems to have little to do with character and everything to do with power.
Overpowering others with our authority, whether by position or personality, is seen to be a mark of positive achievement. The disciples got into trouble in this passage because they were too fond of winning. Many books are devoted to training people to be winners, the assumption always being that victories are more important than relationships. And winning means getting others to serve you. Notice how Jesus responds to his disciples here.