We are told in the letter to 1 Corinthians that the Gospel is "foolishness to those who are perishing" (1 Cor 1:18). Some people understand that to mean that it's okay to be foolish. Take the following true story as an example.
An attendant in the hospital is alone in the elevator with a vulnerable and very anxious female patient. The whirring sound of the elevator and the beep that announces each passing floor are the only sounds she hears. She is on a gurney, staring at the ceiling thinking whatever patients think about when facing the surgeon's knife. Her mouth is dry, due to a pre-op shot she has had. She is being transported to the seventh floor. That's where all 24 Operating Rooms are (called theatres back then). That's where she is going to undergo serious surgery. She has been "prepped". The attendant is a Christian. He is convicted about his pastor's sermon on evangelism the previous week. He thinks this is his moment. Oblivious to her condition, he bends over her, inches from her face and says, "If you should die tonight, and find yourself at heaven's gate, and they ask you the question, "Why should we let you into heaven.." What would you say?"
Although I have altered some details in the story, it does depict a real event. This attendant and I worked together in the operating rooms and he actually got fired for inappropriate comments to patients after the Director of Nursing received several complaints from patient families. He claimed it was persecution. It wasn't so much that he was sharing his faith, but that he was imposing his faith to a captive audience at the most inappropriate times and in very inappropriate ways. He was not attracting people to Christ. He had a knack of repelling them.
So when Paul says that the gospel of God is foolishness to the Greeks, is this what he meant? Did he mean for us to be foolish? Or can we be wise about how to share Christ with our world?