They passed a farmhouse on the left, with a few acres of visible land. Fred imagines that one day, he’ll build a hobby farm on land like that.
"I really want to get a goat," Fred said. "Eggs from the chicks and milk from the goat. That would be awesome."
"Babe," Towanda said, "you don't even drink milk."
"I'd drink it if it came from a goat," Fred said.
Then it was past an Amish house, with clothes stretched out on a line between the house and a side building. They just paid to have a dryer fixed.
"Look at those clothes out on the line," Fred said. "I could have gotten a clothesline or drying rack and it would have been free."
"Babe," Towanda said, "we're not hanging up our clothes outside."
"I didn't even think of that," Fred replied. "It could have been free --"
As Fred laughed, Towanda's eyes made the trip around the car again.
The dialogue does several things: It reveals some things about Fred and Towanda's relationship, which is important to the story; it gives you information about their goals that is essential to the story; and it's funny, which should make most readers like Fred and Towanda, at least on some level ... and that's important to a story, too.
That passage, written another way, could have been a series of paragraphs describing things: Fred said he wanted this and that; Towanda reminded him that he didn't drink milk; Fred said he wants clotheslines but Towanda said no; and maybe there would have one line between quote marks.
When you deconstruct it like that, it's easy to see how much more engaging that dialogue is.