Examples of progressively better thesis statements:
Mark Twain’s Huckleberry Finn is a great American novel.
In Huckleberry Finn, Mark Twain develops a contrast between life on the river and life on the shore.
Through its contrasting river and shore scenes, Twain’s Huckleberry Finn suggests that to find the true expression of American democratic ideals, one must leave “civilized” society and go back to nature.
OR
Eating fast food is bad and should be avoided.
Eating fast food can lead to health problems such as obesity, high cholesterol, and heart disease.
The increase of fast food in the American diet has led doctors to notice increases in rates of obesity, heart disease, and heart attacks in white males.