Jesus' teachings are both easy and difficult to follow. The simplicity of loving God with all of one's heart, mind, and soul combined with loving one's neighbor can lead people to overcomplicate the matter, looking for excuses to not change their lives in meaningful ways. Many people hide from Him behind rules and traditions, claiming to follow His will while still so clearly following what they want His will to be. This is why most of His arguments were with the Pharisees. They insisted that God's will was to follow laws and ordinances in the strictest senses, yet time and again, Jesus pointed out the hypocrisy and emptiness of their devotion to tradition rather than God.
This is why the disciples in today's Gospel left. They were looking for a militaristic messiah who would bring them to power, crushing their enemies in the process. Instead, He told them to love those very enemies. They wanted a royal dynasty to restore the throne of David, and He instead told them to devour His flesh and blood, placing that royalty within everyday people.
Too often we make Jesus what we want Him to be instead of what He is. We do the same for ourselves. We need to be willing to accept the truth about ourselves too.