It’s not true, he explains, that Calvin was the dictator of Geneva.
Calvin did not gain a free hand in Geneva until 1555, when his Libertine opponents miscalculated and allowed French refugees to purchase the right to vote. These refugees were sympathetic to their fellow Frenchman and they swept the Libertines from power. So Calvin only had the run of Geneva for the last nine years of his life. He never became a citizen of the city, but for most of his life was merely a registered alien.
Or that Calvin was the one who had Michael Servetus burned at the stake (happily, that’s not a widespread practice anymore!).
Servetus was killed in 1553, when the Libertines governed Geneva. Calvin visited Servetus in prison and pleaded with him to recant his views. When Servetus refused, Calvin agreed that he deserved to die, but recommended a less painful beheading. The Libertines, ever looking to antagonize Calvin, opted to burn him instead. It is true that Calvin thought that Servetus should die, but so did most everyone in the 16th century, including the Roman Catholics, who were furious that Servetus had escaped from their Viennese prison, thereby depriving them of the honor of killing him.
On a lighter note, Calvin resisted becoming a pastor. However,
in 1536 John Farel pleaded with him to remain in Geneva and help the reform there [as a pastor]; and two years later, after he had been evicted from Geneva, Bucer invited him to pastor a French congregation in Strasbourg. Both times Calvin initially refused, and both times Farel and Bucer played their trump card, “If you don’t pastor these people, then God will curse your scholarship.” Calvin was a sucker for that line, and so he became a reluctant pastor.