"Then they brought the colt to Jesus and threw their cloaks on it; and he sat on it. Many people spread their cloaks on the road, and others spread leafy branches that they had cut in the fields. Then those who went ahead and those who followed were shouting, 'Hosanna! Blessed is the the one who comes in the name of the Lord!"
As Jesus entered Jerusalem, he was greeted as a king by people who expected him to save them. Save them from what? From what we can tell, it seems that they were expecting him to restore their nation to its former glory, to defeat political enemies, and to make them great.
As we know from this most famous story of our faith, these same people who welcomed Jesus as a king would shout to crucify him some short time later. Why? What changed? How did Jesus disappoint them? One way to answer this question is to think about the difference between "The Kingdom of God" that Jesus was preaching about and the political identity of the people. Jesus was preaching about a love that as meant to transform the political system, but the people simply wanted him to help restore the system that they knew and loved.
Jesus was not the king they were expecting. Yet, he was the king they needed. By willingly suffering at their hands, Jesus demonstrated the message of God's kingdom, a kingdom ruled by love and self-sacrifice. Through his death, he won a great victory. It just wasn't the victory they had expected.