Based on the title of the short story and the mention of stones in the beginning of the story, an uneasy feeling worms into the reader's mind. For example, right from the beginning, Bobby Martin has a pocket full of stones and the other boys follow. Also, there is a pile of stones in the corner. In fact, there are five mention of stones in the first two paragraphs. Some astute and sensitive readers may know the purpose of the lottery from these points. Here is what the text says:
Bobby and Harry Jones and Dickie Delacroix-- the villagers pronounced this name "Dellacroy"--eventually made a great pile of stones in one corner of the square and guarded it against the raids of the other boys.
However, the purpose of the lottery becomes clear when Mr. Summer begins the lottery. There is no feeling that people want to win the lottery. Winning is actually losing. So, by the end, when Tessie is stoned, there is little surprise.
As for the reaction of the villagers, this is where it gets very erie. The children seem excited. The adults seem uneasy, but they still do it. They try to pretend nothing is happening. The men speak of farm work and the women catch up on the latest gossip. But no one dissents and says that this is a barbaric and evil practice.