In Mark's account of the arrest of Jesus, only he mentions a naked young man fleeing for his life (14:50-52). Although he didn't acknowledge that he was that lad, most Bible students believe it was Mark. Neither did he mention he accompanied Joseph of Arimathaea to ask for the Lord's body, but only he tells of the conversation between Pilate and the Centurion (15:44-45). If Mark was there, humility prevented him from laying claim to that act of bravery.
Luke's Gospel begins with a humble statement that his account of the events surrounding the life of Christ were taken from "eyewitnesses" (1:2). I am not sure why, but only Luke records information on the family of John the Bapizer (1:5-80). Only Luke records the birth and the first eight days of our Lord's life (2:1-38). And, only Luke records the activities of Jesus which took him most of nine chapters to write (10:1 - 18:14). While Luke is known as a physician, he should be seen as a great historian because of his research and attention to detail.
John's focus, unlike the Synoptic writers, is on the deity of Christ, the ultimate in humility. The others describe their three year journey with the Man, Christ Jesus, but John presents Jesus as God, as Creator (1:1-3, 14)! What man could not be humble when in the very presence of God, Himself? John's Gospel includes a vast amount of material that does not appear in the Synoptics (1:1 - 12:11; 14:1-31; 15:1 - 17:26). Many Bible students believe that John's awareness of the Lord's great love for him, was what he found so amazing; he mentioned it three times (20:2; 21:7, 20). Because John was the only disciple who was not martyred, many believe John 21:22 identifies him as the beloved one.
If you were to write a Gospel, what could you share of your relationship with Jesus?