Why are you not suppose to put bananas in the frig?!
Answers: It turns their sugars into starches, just like tomatoes. They'll keep longer but their flavor and texture will be affected. If you're going to cook them, say, in a bananas foster, then it wouldn't matter as much.
The skin will go black is why.
Some people actually think they turn poisonous in the fridge - stupid.
They will last much longer in the fridge.
Maybe you don't like the darker skin from the fridge but it is nothing like they will be when they are out and mushy with flies hovering if you keep them out.
Throw them in the freezer once they are good for cooking only.
They are a tropical fruit. They aren't meant to be kept in the cold.