One reason people got so excited about Jesus was because they believed He was going to lead a revolt against the Romans (who occupied their country). In other words, they thought Jesus had come to establish a new political kingdom, with Him as its king.
But this wasn't Jesus' plan - nor was it the reason why God sent Him into the world. In fact, Jesus deliberately went out of His way to show that He had no intention of seeking political power. On one occasion, we read, "Jesus, knowing that they (the crowd) intended to come and make him king by force, withdrew again to a mountain by himself" (John 6:15). On another occasion, He declared, "My kingdom is not of this world" (John 18:36). Once people realized this, many turned against Him.
Why, then, did Jesus come? Jesus Christ came for one reason: To bring us back to God. We are separated from God because of our sins, and our greatest need is to have our sins forgiven and cleansed. But how is this possible? It's only possible because Jesus Christ was willing to take all our sins upon Himself, and become the final and complete sacrifice for our sins. This is what He did when He died on the cross for us.
Many people, however, weren't willing to admit they needed a Savior - and the same is true today. May this not be true of you, but by faith open your heart and life to Him without delay.