What I get most in the US are comments on what I am buying: "What will you be preparing with these?", "Yum, I can tell someone's going to be very lucky tonight", or "How do you prepare XYZ?". Sometimes, if they hear me talk and are perceptive "Do I detect an accent?". A few times, comment on the way I dress, especially if a piece is a bit unusual: "You didn't buy this skirt here, did you?", "That's an extraordinary sweater", etc.
In France, the approach is typically wittier, designed to get you off balance. This male cashier recently asked me: "Do you enjoy jogging?" Me: Euh, no, not particularly, why? "Because you forgot to price your apples" (in France, you weigh your fruit and veggies before getting to the cashier)
While purchasing a bottle of Montbazillac, the customer behind me, upon hearing me tell the cashier I intended to cook with the Montbazillac suggested I cook with his bottle of vodka, and we share the Montbazillac.
A few jokes went back and forth on the vodka/culinary theme.
In the end, I think it all depends on the mood, receptivity and sense of humor of the lady in question, so nobody should feel they have failed in any way if they get somewhat of a cold shoulder.