We don't get to know Shoba that much since her story is told through her husband Shukumar. What we do know though is this: she's a total, organizational neat freak who plans ahead—like way ahead:
When she used to do the shopping, the pantry was always stocked with extra bottles of olive and corn oil, depending on whether they were cooking Italian or Indian. There were countless boxes of pasta in all shapes and colors, zippered sacks of basmati rice, whole sides of lamb and goats from the Muslim butchers at Haymarket, chopped up and frozen in countless plastic bags. (ATM 19)
You know Shoba because she's that person: the one who can spend hours browsing the aisles of The Container Store on weekends.
We're guessing too that she probably would have made a great mom because she's the kind of person who "used to put her coat on a hanger, her sneakers in the closet, and she paid bills as soon as they came" (ATM 17). In other words? She's the responsible adult in the marriage (for more, go check out her hubby's link—"Shukumar").
That all changes after she gives birth to her stillborn baby. Suddenly, Shoba's leaving her coat and shoes right where she takes them off (ATM 17).
She stops caring about her appearance, wearing grey sweats underneath her raincoat, "looking, at thirty-three, like the type of woman she'd once claimed she would never resemble" (ATM 1).
But who can blame her? At least she's still able to get up in the morning and go to work, which is a lot more than what Shukumar can do. And clearly, she still has her wits about her because she's able to plan for her separation from Shukumar.
She's also the one to come up with the "game" they play during the blackouts, so she's vitally important to the movement of the plot.