There are several themes identified in Shirley Jackson's "The Lottery." Those that resonate with me are violence and cruelty, and custom and tradition.
In reading the story the first time, we are probably struck by the sense of the "everyday" in terms of the characters and plot. This sense of the ordinary is what creates an environment of surprise and horror when the plot becomes apparent to the reader. It rattles the reader with Jackson...
...suddenly interjecting into a seemingly ordinary environment the horrifying reality of the lottery.
First and foremost is the theme of custom and tradition. This particular activity has been going on for years. There is vague discussion that other towns nearby are doing away with it, though we don't know what "it" is when this statement is made. The fact that everyone is so accustomed to doing the same thing each year and that no one questions it is a part of the human condition. How long did slavery continue in this country until it was finally challenged? How long did it take for women to earn the right to vote in the United States? The status quo is part of the comfort of the human condition: doing it because it has always be done "this way."
Another element of the human condition is the lack of concern as long as one is in no danger. Conversation when everyone arrives is mundane: with small talk and kidding. Even Tessie is involved. Her attitude changes dramatically when her family is targeted by the lottery. She speaks out in fear to complain, and her husband tells her to shut-up. The other families are "off the hook," so they can have no sympathy for Tessie and her family: "Better-you-than-me" is the prevalent attitude. No one has any patience with Tessie's resistance because it cannot touch them, another aspect of the human condition.
The last element I notice is Tessie's complaint that her daughter and her husband are not included with the family. A mother would generally do anything to protect her children, but Tessie's desire to survive is a basic instinct. When reason disappears in the face of disaster, a survival instinct comes into play. We see this with the rush of adrenaline one feels during a time of emergency when someone is excessively strong or fast in the face of danger: it is an animal instinct.
The aspect of violence and cruelty is also a part of the human condition. It has been a part of mankind's behavior since the beginning of time, with the murder of Abel by his brother Cain. People throughout history have found the most horrific ways to punish the human body, though it may be disguised as an honorable task, as with the Spanish Inquisition. In this community, the violence and cruelty of the lottery is as much a part of the community's standard behavior as a community picnic or a funeral. It is accepted by the community in general, no one questions it, and in light of this, no one is guiltless in the act as it is carried out year after year.
The human condition is evident throughout "The Lottery." Custom and tradition allow for this violent and cruel practice to continue year after year. Those who are not personally affected have no sympathy for those who are. People are satisfied as long as it does not harm them. No one takes a stand against this brutal custom because it's always been done this way. The victim does all she can to avoid her death—a survival instinct attempting to avoid a sentence of death. These are all aspects of the human condition.