The mother and the neighbor?

What was the big deal between Apu’s mother, Sarbojaya, and the neighbor who lives upstairs, Nanda? The first time he shows up to give her a calendar, she pulls her head scarf over more of her hair and leaves the room. The second time, when she hears him coming, she pulls the scarf over her head and hides until he has gone upstairs.

When she needs some matches, she asks Apu about him, and then tells Apu to ask him for just two matches, as if she dreadfully feared being in his debt for an entire box of matches. Apu goes upstairs and watches him surreptitiously, as if he were doing something of significance, but all he does is unwrap a bottle of booze. Apu asks for just two matches, but Nanda gives him the entire box, saying he has plenty and that Sarbojaya needn’t return them.

Then, while her husband is sick, she is preparing food. Nanda enters her kitchen to ask her if she has some paan. It doesn’t sound like a big deal, but it is filmed as if his approach is ominous. She is fearful, and then turns on him, furiously telling him to get out. When he leaves, she breathes heavily, as if she just escaped being raped or something.

Is she crazy? I have known women who always think every man they meet is on the make for them, when the men actually have no interest in them at all. Or has Nanda violated some terrible taboo, like, “Thou shalt never ask thy neighbor’s wife for paan?” And if it is such a big deal in India, why don't they get doors they can close to keep neighbors from just walking in without knocking?

Whichever it is, what the heck does it have to do with the rest of the movie? With all that buildup, we expect some great climactic scene, but there is no payoff.