At first this section of Mark might just seem like two slightly connected stories about Jesus’ disagreement with the Pharisees and warning the disciples to be on the watch for the yeast of the Pharisees. Then after he gets off the boat Jesus heals a blind man. But I think that all three of these stories are connected, the first and the last sandwich the second. Jesus starts out by telling the Pharisees that they will not be given a sign, but then in Bethsaida he heals the blind man, thus giving the man and the disciples a sign. So there is all the bit in the middle that is odd, stuff about yeast and Jesus berating the disciples for thinking he was actually talking about yeast. So what could Jesus actually be talking about?
It seems that Jesus is telling the disciples to not be like the Pharisees and Herod and worry about superficial signs of his ministry. He wants them to understand his actual ministry is focused on the putting the world to right through the Cross and Resurrection. But he is also there to prove he is from God by miraculous signs, healings, and forgiveness. But when they start to worry about the only one loaf of bread that they brought he reminds them of how he did so much more with a few loaves of bread. Jesus is teaching the disciples that they do not have to worry about their physical needs when they are with him. He and the Father will take care of their needs.
Then to really drive home the fact that he does have power from the Father, Jesus heals a blind man when they reach the other shore and the city of Bethsaida. However, Jesus does take him out of the village and heals him. Of course in the Jesus fashion he tells him not to tell anyone; he also tells him to not even go back into the village. So this is a sign for this man, his family, and the disciples.
At this point I would offer some encouragement, trust me there are a lot of times that we are going to misunderstand God. He might say something obscure to us like Jesus did to the disciples; we might try to understand it in light of a situation we are in right now. But God might mean it in a way we did not think about. However, God is good and he will have to explain it to us like the children we are. Saying you might have thought I meant this, but really I wanted to show you how I was working here. My family and I have had to deal with this recently. We thought God was going to have things happen one way. But instead things worked out very differently and he has taught us to live more simply and rely on people, allowing us to see how much we are really and truly loved. God does this quite often, you have probably heard about the footprints in the sand. Someone looks back and only sees one set of foot prints and they ask God where he was, he says he was caring them at that point. But usually we look back and see a long ditch in the sand. When we ask God what happened there, he usually says that is when I had to drag you, because you did not want to walk with me or you saw something that distracted you from where I was leading you. So understand that usually God is going to drag you because we are stubborn and not willing to just let him carry us/care for us.