For as long as I can remember, whenever I'm presented with a choice between a small and a large box in a video game or something, I've had the idea that I should pick the small box rather than the large one. It's similar to The Honest Woodcutter, so I imagine it's also from some sort of fairy tale or fable, but I'm just not sure.
It's from scores of fairy tales. There is the trope where asking for one means you get given the other, but there is the trope where the less impressive looking thing is the more powerful.
The casket itself is used in The Two Caskets
The girl left the room to go to the loft, and as soon as she got outside, she found all the cats waiting for her. Walking in procession, as was their custom, they followed her into the loft, which was filled with caskets big and little, plain and splendid. She lifted up one and looked at it, and then put it down to examine another yet more beautiful. Which should she choose, the yellow or the blue, the red or the green, the gold or the silver? She hesitated long, and went first to one and then to another, when she heard the cats' voices calling: 'Take the black! take the black!'
The words make her look round—she had seen no black casket, but as the cats continued their cry she peered into several corners that had remained unnoticed, and at length discovered a little black box, so small and so black, that it might easily have been passed over.
with the consequence that
then she placed the little casket on a small shelf in the corner.
'Now I may open it,' she said to herself; and unlocking it with the key which hung to its handle, she raised the lid, but started back as she did so, almost blinded by the light that burst upon her. No one would ever have guessed that that little black box could have held such a quantity of beautiful things! Rings, crowns, girdles, necklaces—all made of wonderful stones; and they shone with such brilliance that not only the stepmother and her daughter but all the people round came running to see if the house was on fire.
But later, another girl choose differently
There were the caskets, blue and red, green and yellow, silver and gold; and there in the corner stood a little black casket just like the one her stepsister had brought home.
'If there are so many jewels in that little black thing, this big red one will hold twice the number,' she said to herself; and snatching it up she set off on her road home without even going to bid farewell to her mistress.
with the consequence
So mother and daughter carried it proudly upstairs and put it on a shelf over the fireplace; then, untying the key from the handle, they opened the box. As before, a bright light leapt out directly the lid was raised, but it did not spring from the lustre of jewels, but from hot flames, which darted along the walls and burnt up the cottage and all that was in it and the mother and daughter as well.