The divorced mother of two -- still smooth-skinned and ash blonde at 52 -- was always glad to share talk of her beloved Red Sox baseball team, gardening and a growing enthusiasm for target shooting.
But while Lanza spoke proudly about her sons and brought them in for breakfast when they were younger, friends say she held one card very close: home life, especially its trials and setbacks, was off limits.
Now, the secrets Lanza kept are at the centre of the questions that envelop this New England town, grieving over the slaughter unleashed by her 20-year-old son Adam.
"Her family life was her family life when we were together. She kept it private. That was her own thing," said Louise Tambascio, who runs the warmly lit pizzeria.
Friends had met Lanza's younger son, who stared down at the floor and didn't speak, when she brought him in. They knew he'd switched schools more than once and that she'd tried home schooling him.
But while she occasionally expressed concern about his future during evenings at the bar, she never complained about anything at all.
"I heard her as a parent. I always said that I wouldn't want to be in her shoes.
"But I thought, 'Wow. She holds it well,'" said Tambascio's son, John.
Nancy had previously worked as a stockbroker in Boston and her husband was a successful executive.
When the couple divorced in 2009, he left their spacious home to Nancy.
The split was not acrimonious and Adam spent time with both his mother and father, she said.
Those who knew Nancy Lanza recall her as very generous, often giving money to those she met and doing volunteer work.
When a mutual friend sought a loan from an acquaintance, Jim Leff, and Leff asked for collateral, Lanza intervened.
"Nancy overheard the discussion, and, unblinkingly, told him she'd just write him a cheque then and there," Leff recalled.
Neighbours knew her from the monthly gathering of women who rotated between homes for games of the dice game bunko. Lanza enthused about gardening, and also began telling friends that she'd bought guns and had taken up target shooting, John Tambascio said.
All three of the guns that Adam Lanza carried into Sandy Hook Elementary were owned and registered by his mother -- a pair of handguns and a .223-calibre Bushmaster rifle, his primary weapon.
"Guns were her hobby," her friend Dan Holmes told The Washington Post. "She told me she liked the single-mindedness of shooting."
But while trips to shooting ranges gave Lanza an outlet, she returned home to the ever-present challenges of raising a son with intractable problems.
At Newtown High School, Adam Lanza was often having crises that only his mother could defuse.
"He would have an episode, and she'd have to return or come to the high school and deal with it," said Richard Novia, the school district's head of security until 2008.
Novia said Adam Lanza would sometimes withdraw completely "from whatever he was supposed to be doing," whether it was sitting in class or reading a book.
Marsha Lanza described Nancy as a good mother.
"If he had needed consulting, she would have gotten it," Marsha Lanza said. "Nancy wasn't one to deny reality."
But friends and neighbours said Lanza never spoke about the difficulties of raising her son. Mostly she noted how smart he was and that she hoped, even with his problems, that he'd find a way to succeed.