Grandfather awakens to the sound of the lawn mower, the sound that to him means the beginning of summer. He looks out the window and sees one of the boarders, Bill Forrester, a newspaperman, mowing the lawn. He goes downstairs to eat Grandma's breakfast, raving about the lawn mower, where he is informed by Grandma that Forrester intends to put in a new kind of grass that does not need cutting. Grandpa is alarmed and goes to talk to the newspaperman who shows him the new grass. Grandpa tells Bill that the problem with his generation is that they are always trying to save time. But in reality it is the little things in life that bring so much pleasure, especially since the big ones cannot be solved. Spending time with nature in such a little way as mowing the lawn or picking dandelions allows you to get away from everything—other people, the town—and just be yourself for a bit. It gives you time to think freely, to philosophize. Grandpa asks Bill how much the new grass cost and pays him the ten dollars that Bill had spent plus five more to take it all to the ravine and get it away from his lawn. Later that day Grandpa hears Bill cutting the lawn again.
Leo Auffmann is having trouble figuring out what should go into his Happiness Machine. He begins asking Lena questions about her happiness but only succeeds in getting them into an argument. She points out the stupidity of standing there questioning whether or not she is joyful while she scrubs the sink, and while they are arguing the bread burns in the oven. Leo retreats outside and begins working. For two weeks he works, barely seeing his family, and then one day announces to them that the Happiness Machine is ready. His wife points out that he has not spent time with his children and they are nervous and fighting, that he has lost weight and she has gained weight, and that the machine has certainly not helped make anything happier.
The next day Leo listens while Lena again attacks the machine, arguing that if it has no answers to death or babies then it is useless. Leo is still convinced that it will be useful but then that night he wakes up and hears his oldest son Saul crying. Saul was weeping after using the machine. The next morning Lena is furious and is sorting out their stuff, threatening to leave. Leo pleads with her at least to try the machine and she does so, seeming at first to be enthralled but then she begins to weep. His wife explains to him the problem with the machine: it shows people all of the things that they will never get a chance to do in their lives and the knowledge that they will not get to do those things becomes terrible. The machine is great until you realize that you must leave it and that outside are none of the things the machine shows—Paris, London, Rome, etc. And as long as it is out there they will want to visit it, just to see, even though they know it will cause only sorrow. Leo is still in disbelief and he wants to try it himself but when he does the machine sets on fire and burns, along with their garage. The whole town gathers to watch the fire and Leo sits outside and thinks. While Grandpa and Douglas and Tom listen he explains to them his mistake. He realizes now that the real Happiness Machine has always been there—his family.
Bill Forrester learns the lesson that what we think of as progress is not always necessarily a good thing. It may be that certain chores, such as mowing the lawn, actually fulfill an important role in our lives. Grandpa explains to Bill the importance of the lawn mower, and it is a lesson that Bill takes to heart. Sometimes it is necessary to do something that lets you get away, if just for a moment, from everyone else and to simply be yourself. During that time it becomes possible to truly think for yourself, and Grandpa goes so far as to suggest that it is during these times that people truly philosophize. If there are no answers to many of the big things in life, then our best understandings come from the little things that we do, and Grandpa teaches Bill that if we do not hold on to some of those little things we could become lost among the big issues that are too big for us to handle. This is another way of saying that we should remain close to nature. Because in the end, although we are seemingly in constant battle with nature, we are also an integral part of the natural world. Therefore, if we wish to understand our lives we cannot divorce them entirely from simple things like mowing the lawn, or picking dandelions.
Leo Auffmann learns a similar lesson. He learns that in some ways we have to remain close to nature. Although much can be automated and made into a machine, our emotions cannot be divorced from ourselves. Happiness comes from interaction with people, and no machine can ever replace what people mean to us. Lena knew all along that they had happiness right where they were, and this is another important point. It is a part of the mechanical mindset to continually look to find ways to make things easier and improve upon what we have. However, to improve some things is to destroy them. In Leo's case, his family life, the love of his wife and children, is sacred, and the changes that his Happiness Machine made in the way his family lived threatened to pull it apart. The magic of summer is to bring families together out in the open air, and his machine threatened that solidarity. Once it is destroyed, he can return to living with his family the way they did before. The Happiness Machine itself was doomed to failure, but modern culture has many reincarnations of such a machine. Television, radio, computers, movies, all can be used for the sole purpose of providing happiness, and it seems that Bradbury is issuing a grave warning—these devices will serve only to divide the true happiness that arises from the unity of family life.