The danger of using Christ most often as an exemplar, is that we begin to believe our behavior is the gospel. Don’t confuse your Savior with your behavior. In fact, when we fearfully begin considering what the “Christian-thing-to-do” is in a given situation (WWJD), we have probably already forgotten Christ’s work for us. Instead of having a debate with your conscience, call Satan out from the shadows and tell him how much Christ loves you. Martin Luther writes:
To those that are cast down on account of their sins Christ must be introduced as a Savior and Gift, not as an example. But to sinners who live in a false assurance, Christ must be introduced as an example. The hard sayings of Scripture and the awful judgments of God upon sin must be impressed upon them. Defy Satan in times of despair. Say: “O cursed Satan, you choose a nice time to talk about doing and working when you know very well that I am in trouble over my sins. I will not listen to you. I will listen to Christ, who says that He came into the world to save sinners. This is the true Christ and there is none other. I can find plenty of examples for a holy life in Abraham, Isaiah, John the Baptist, Paul and other saints. But they cannot forgive my sins. They cannot procure for me everlasting life. Therefore I will not have you for my teacher, O Satan.”
The danger of thinking “what would Jesus do?” all the time, is that you forget what Jesus has done. It is entirely possible to live obsessed with the creed WWJD and not be a Christian, but only a Christian can cast his cares on Christ in times of trouble. To believe in Jesus is not to believe in morality. To believe in Jesus is to disbelieve the divinity of our morality – to realize our morality is not enough to fend off despair or eternal death. Only forgiveness in Christ can do that. And in Him there is forgiveness of sins for you.