Moody's Anecdotes, p. 123
John Wesley used to ask his young men whom he had sent out to preach on probation two questions: "Has anyone been converted?" and "Did anyone get mad?"
If the answer was "No," he told them he did not think the Lord had called them to preach the Gospel, and sent them about their business. When the Holy Ghost convicts of sin, people are either converted or they don't like it, and get mad.