In the story, the lottery is overall a rather relaxed, natural occurance. How do you think you would feel if you were there?
If I were somehow transported into that village at that time from my own environment, I would undoubtedly feel horrified and want to get away from the place quickly and very surreptitiously. However, if I had been born and raised there, I suppose I would accept it as a normal part of life and a interesting break from the dull routine of rural existence. I would also feel it was an important and necessary part of village life.
My main concern, of course, would be in whether I myself might get the fatal slip in the lottery. If somebody else got it, I would feel relieved and probably happy. If a friend or relative got the death slip, I would undoubtedly feel dismayed but would assure myself that, after all, everybody had an even chance and that everybody has to die sooner or later. The one who is getting stoned to death is serving an old tradition and making a sacrifice for the good of the whole communiity.
As many as, let us say, five hundred people may play bingo at a casino. When one person gets the final winning number she is joyful and yells, "Bingo!" But there are 499 people who are dismayed and disappointed. If asked whether she didn't feel sorry for the losers or guilty about taking their money, she would probably say, "They all had an equal chance." I think most people are vastly more concerned about themselves than they are about others. Virginia Woolf once said, "People care very little about each other."