How many signs would have been sufficient for them to believe? Jesus had already performed a number of miracles there in Capernaum (i.e. a man in the synagogue with an unclean spirit (Mark 1), Peter’s mother-in-law (Mark 1), the sick and demon possessed (Mark 1), Centurion’s servant (Matt. 8)) What is necessary for us to believe?
Do we want Christ's gifts without the Cross? Do we seek to use Him instead of asking Him to use us as He sees fit? If He does not rule over all of my life then He is not truly my King.