The Question and Answer section for Our Town is a great resource to ask questions, find answers, and discuss the novel.
small town life is better than living in large cities
Our Town is set in the fictional town of Grover's Corners, New Hampshire (population: 2,642). I suppose it is small enough that all the characters are familiar with each other, which serves the narrative of the play.
I think the stage manager is saying that you must charish life. Sometimes it takes a lifetime to understand how special life is.