When Jesus issued the invitation to follow him he didn't tell them up front where he was going or leading them to. Which is amazing. They knew he was a Rabbi. They were honored they were being drafted by a Rabbi to follow him. Which would have been contrary to how an individual usually entered into a Rabbi/disciple relationship.
So they got up and started following.
They would have been impacted by the messages they were hearing. This Rabbi was teaching differently, as one who had authority. He was teaching about life in the kingdom of God now, not just for the age to come. He was raising the bar concerning thought life and motive and actions. Maybe not raising the bar but showing where it should have been all the time.
Then they observed his actions. How he spoke to women. How he mixed company with unclean people, like those with leprosy. How he spoke to sinners and tax collectors. How he healed a variety of people. How he exercised authority over demons. How he raised Lazarus from the dead. How he spoke to the religious authority. He was different.
At times he had an edge, but it was not mean spirited. At times he was blunt, but not obnoxious. All the time he spoke truth. He was open about his agenda.
People down through the ages have looked at the life and teachings of Jesus and have come to a variety of different conclusions as to what he was all about or what he was leading his disciples to become. He had a goal in mind. He still has a goal in mind.
Love. God and others.