The first fridge we see is Aunt Gladys's. Neil tells us that "whichever [fruit] I preferred, there was always an abundance of the other jamming her refrigerator like stolen diamonds" (1.45).
Gladys is a person who worries a lot about not letting anything go to waste. She's obsessed that the food in her fridge be used before it spoils. Neil says he hopes Gladys "dies with an empty refrigerator, otherwise she'll ruin eternity for everyone else, what with her Velveeta turning green, and her navel oranges growing fuzzy jackets down below" (1.45). Aunt Gladys's fridge represents attention to conservation of resources, but also a kind of opulence. Instead of needing to fill her fridge, Aunt Gladys needs to empty it.
Neil relates all this sarcastically, and even slightly disdainfully, which might explain his willingness to glut himself on the abundance of fruit in the Patimkins's fridge. Their fridge is beyond Aunt Gladys's perpetual filling and emptying, and seems to simply grow delicious fruit (that never spoils) all on its own—like magic. Their fridge works with the sporting-goods trees as a symbol of a version of the American dream. It also highlights the luxurious lifestyle in Short Hills. The fridge helps to complete the analogy that Neil is a conqueror-explorer invading the paradisiacal suburbs, conquering daughters, and, as Julie puts it, "stealing fruit" (3.45). At the end of the story, which fridge might Neil prefer? And which other "cherries" might he steal (Wink, wink)?