Katrina Dawson didn't like coffee.

"It was her only flaw," my sister Bee said. "And it was the one that killed her. If she hadn't preferred hot chocolate, she might not have been in the Lindt Chocolat Cafe."

Katrina - "Tree" as they called her at school - would have appreciated the irony, even on the day of her death. Though she excelled in every field she chose to pursue, her wicked sense of humour proved she never aspired to become a paragon of virtue.

Tree grew up in Randwick, with a rope ladder over her back fence into our backyard. That rope ladder brought her into our kitchen and stole away my older sister to games of Marco Polo that I could hear from our garden.

Every afternoon after school, the three of us and Clare, who lived down the road, would hop off the bus and bounce straight into the corner store, where Tree would buy a bag of lollies for us to share. This was a devious act, as eating in uniform was forbidden under the school rules, and so it was with sad stomachs that we stepped off the bus on the day that Tree was inevitably made a prefect. Surely now she must observe the school rules. But incredibly, she led us straight back into the corner store. Her commitment to friends and lollies trumped her commitment to the badge.

Tree's generosity and loyalty were legendary among her school friends.

Reports that she had been shielding her pregnant friend from the gunfire rang absolutely true.

"She would have been the one looking after everyone," said Clare.

At 9.15am on Monday, Katrina told her clerk that she was going out for hot chocolate, and headed to the Lindt Chocolat Cafe with barristers Julia Taylor and Stefan Balafoutis. With three children to ferry across the eastern suburbs to school, she often had to wait until the mid-morning for the chance to eat a piece of vegemite toast and a hot chocolate.

Jeremy Stoljar SC, a close friend and mentor who worked with Katrina at the Eighth Floor Selborne Chambers, dropped into her office to say hello, and again 20 minutes later, only to learn she was still out. Soon after news of the siege broke, her husband, Paul Smith, tried to reach her on her mobile.

Tree was admired by almost everyone she met, none more than her children, for whom the feeling was entirely reciprocated.

Even when her youngest had reflux, she took it in her stride. "Mummy you live in vomit land," her oldest daughter said. "It's true," she replied.

"She was a terrific barrister, she had first class legal skills, and more importantly she was a wonderful person," Jeremy Stoljar said.

"She was a very funny, loving person, very popular, very caring person. I can't believe we're having this conversation."

Female lawyers contemplating a move to the bar were often advised to speak to Katrina before they did so. She was the person that seemed to make motherhood and a career at the bar work.

Former Governor General Quentin Bryce was in tears. She had been the principal at the University of Sydney's Women's College while Katrina was senior student at the hall of residence.

"Our country has lost a shining star," Ms Bryce said.

"Confident, courageous, out-front, articulate, warm and funny, but thoughtful, gentle and understanding too."

This is not how it was supposed to end. Tree was always the girl most likely to succeed. She was not supposed to be killed in a madman's frenzy.

Earlier this year Tree went on holidays to Turkey with her mother.

The day she died was her mother's birthday.