It isn't easy to break old, unhealthy habits, to
rebel against mainstream society, to differentiate yourself from family and friends, to take a moral and ethical stand each moment of every day with every action you take, etc..
From wiki: «Maccoby argued that the real Jesus was not a
rebel against the Jewish law, but instead a Jewish Messianic claimant whose life and teaching were within the
mainstream of first - century Judaism.