While many of Bradbury's short stories discuss the negative consequences of technology upon American families, the three stories that you have read possess a different set of similarities. Below are some common themes.
1. All three stories feature Americans partaking in common activities of the late 1940s and 50s. In "The Garbage Collector," a husband and wife who normally eat dinner together discuss a change in his job. In "The End of the Beginning," a father mows the lawn, and he and his wife later discuss their son's journey into space. In "I See You Never," a landlady with children is about to sit down to dinner with her family when the story's action begins. Bradbury uses these seemingly common elements to depict an idyllic America--one in which families communicated and ate meals together.
2. Bradbury also uses these stories to express an uncertainty about the future. "The Garbage Collector" and "The End of the Beginning" demonstrate a concern about how the threat of nuclear attacks and the success of the space race will affect average Americans. In "Garbage," the husband's mundane job is about to change into the nasty business of corpse cleanup in the event of an atomic attack. "End of the Beginning" is not as negative, but the parents in the story realize that their son's future will be far different from their lives and wonder if the changes are a good end to their era. While "I See You Never" does not discuss the effects of technology or scientific advances, it does deal with the future of immigration and how America will handle those immigrants who help the country (in this case, during World War II) but whose papers have expired. Mr. Ramirez, one of the story's key characters, is a law-abiding immigrant whose visa has run out; so he must return to Mexico. His landlady realizes that she will never see him again, despite the fact that he has helped the country, is a good tenant, and has grown accustomed to the conveniences of American living. Bradbury raises the question of what America's obligation is to immigrants like Mr. Ramirez.