In preaching on Mark’s version of the Parable of the Sower, Tom Long claimed that Jesus preached in these confusing parables in order to make people deeper thinkers about what the gospel is all about. Jesus did not want to have people grab the gospel too quickly because such a quick grab almost always resulted in bad faith or shallow faith that did not last long (a point made within the Parable of the Sower itself, of course).
In that connection of wanting people to grow deeper, Long told this story:
The great preacher George Buttrick was once flying on an airplane. As he sat there, he had a legal pad out on which he was furiously scribbling some notes for his sermon the coming Sunday. The man next to Buttrick inquired, “Say, what are you working on there, sir.” “My sermon for Sunday–I’m a Christian preacher.” “Oh,” the other man replied. “Well, I don’t like to get caught up in the complexities of religion. I like to keep it simple. You know, ‘Do unto others as you would have them do unto you.’ The Golden Rule! That’s my religion!”