Why?
I recently answered that very question on Facebook and, not wanting to see those thoughts disappear forever below random clicks of things I "like," I'll reproduce my answer below:
Luc Travers would probably be able to answer this better than I can but here's my quick "reading" of the painting:
The subject is a girl with a mandolin--some type of instrument that she seems to have been playing.
She is in the snow but, aha, is hardly dressed for it. In fact, she's wearing a sleeveless dress and trying to keep herself warm. Experience suggests that this is not going to work and isn't at that moment.
But on her face there is no suggestion of persistence--"I'm going to stay warm or figure out how!" Her eyes are cast downward and if I put myself in that position, what do I feel? Regret.
So this woman is regretting something. What? We can imagine she regrets playing so much rather than preparing for this moment. In fact, the message I take from this painting is "prepare for the winter before it comes."
As to connections with shopping, the American consumer has little savings if not a lot of debt. Meanwhile it's not hard to imagine a snowstorm--i.e., economic crisis--as the "snow" is already in the sky. Winter, in my view, is here and it's about to get even colder.
So news that Americans went "shopping like there's no tomorrow" reminded me of this mandolin player--who herself is representative of the Grasshopper (in Aesop's Fables). She hasn't prepared for the future [and] is now dependent on anyone who has.
There are a lot more connections here, however, and Luc would undoubtedly stress the more personal ones. For example, this painting is a nice concretization of not preparing for an important meeting, or test, or challenge.
Although beautiful, I love this painting for the above things (much of which I probably wouldn't have noticed if I hadn't read Luc's book on the subject, Touching The Art).