what evidence is there that stowe believes the idea of a happy, cheerful slave is ludicrous

Although Eliza may reprimand her husband to try to feel more like a Christian, it is obvious that Stowe writes of George with only the highest regard. She uses positive, heroic adjectives to describe George's rebellious thoughts and headstrong attitude. Indeed, he fights, but it is for liberty. The fact that George is willing to die for his freedom is Stowe's way of emphasizing her point that no slave, whether docile like Tom or rebellious like George, would ask to be reborn in his or her position. There is no such thing as a happy slave. A man belonging to another man is inherently the worst form of human existence.