How did Paul turn pagan idolaters into believers if he had nothing physically impressive about him?

Les explains that Paul entered cities like Thessalonica, Berea, Athens, and Corinth—places full of abject pagan idolaters who knew nothing of the God of creation and were morally rotten. Into that environment walked a man with no pleasant appearance and nothing physically going for him. All he did was preach Christ crucified, and those people turned from their idols and became believers. Les says the explanation is the power of God when the Gospel was preached, and he sees the same principle at work today. The early believers became so staunch that they were willing to be martyred by the hundreds, never wavering, panicking, or running. Les compares that to modern times, noting that while our moral fabric seems to rot, the Roman Empire was worse, and there is still hope because most Americans have some concept of God, with polls suggesting two-thirds believe they will stand before God.