When I was first getting to know Nicole Davis back in November 2010, she and her husband Tyler invited me over for dinner. Nicole was dressing a salad and talking lovingly to her toddler daughter, Abbey, when I arrived. A little over a year earlier, when she was 25, Nicole had been diagnosed with an aggressive form of breast cancer while pregnant with Abbey.

After a year of surgeries and chemotherapy—during which she gave birth to Abbey—she appeared to be healthy and recovered. Over salad and lasagna, she and Tyler looked to the future: Nicole was considering a preventive double mastectomy to minimize the chance of a recurrence, and they were discussing adopting a child sometime in the future. Family was their highest priority, and a year of aggressive cancer treatment and the birth of their daughter had only strengthened their fierce love and resolve. Among their family “village,” as they called it, they had a code of solidarity: EOUIAOU, “Each one of us is all of us.”

Nicole and I talked about how her story of triumph over breast cancer at such a young age could raise awareness about the still-rare, yet rising incidence of the disease among women under 35, as well as serve as a beacon of hope and inspiration. How could we know that night, as we talked about their family and their plans and Abbey smiled and babbled in her high chair, that in a couple of months, that “preventive” double mastectomy would wind up revealing that the cancer had spread to her liver?

Most of us, though we know on some level that we’re not immortal, tend to live as if we are. Maybe it’s ignorance, or maybe it’s just a natural self-protective defense. We put off doctor appointments or following through on a pledge to eat healthy or be kinder to our bodies. We avoid difficult conversations and tell ourselves that we can wait to resolve an issue with someone we love, because, after all, there’s always tomorrow. We forget to be awed by our children’s smiles, and the wide blue sky, and the sweet smell of spring, because we’re preoccupied and distracted. And yet, as the Buddhists like to say, “Death is certain, but the time of death is uncertain, so what is the most important thing?” How might we live, what would we be like, if we constantly asked ourselves that question?

When I had lunch with Nicole in February, after 18 months of chemo as part of a clinical trial, she shared what it was like to live with Stage 4 cancer. She’d lost weight and moved a little slower than I remembered, and she acknowledged that the treatment, and the fear of cancer reappearing, had taken a toll. Her immune system was weak; she tired easily. Even so, her characteristic beauty and spirit shone bright: Her big, blue eyes, her wide smile; her short blond hair, which she’d chopped in various funky ’dos as it grew out; her humor and penchant for being silly and having fun; her ability to make you feel like a treasured friend and confidante; her gift for showing strength and vulnerability all at once.

“Life deals you these cards,” she told me. “Sometimes you get a good hand, sometimes you don’t. Unfortunately, we’ve been dealt a horrible hand. You can either fold and not try to win, or you play them and see what you can do with them. The silver lining for me is that I get the opportunity to look at the tiny things that could matter the least to someone, and have such an appreciation and joy for those things. The fact that my daughter gets to grow up in that is really important. It’s like an echo effect. She’ll be able to carry on that empathy, compassion, and joy that not a lot of people get to grow up around.”

As she fought for her life and hoped for a cure, she succeeded in living these past two years as if it were a sacred gift. She spoke at Susan G. Komen events, posing in a bright-pink wig or appearing with her blond hair streaked with magenta and styled like P!nk, one of her favorite artists. She photographed Abbey at ballet class. She celebrated her and Tyler’s fourth and fifth marriage anniversaries. She went out for manis and pedis with her closest girlfriends, took a trip to Vegas, went dancing and attended a family reunion. In August, she dropped off Abbey at her first day of pre-Kindergarten, affixing a large pink bow to her daughter’s long brown ponytail and exclaiming on Facebook: “She is growing up so fast! This momma is having a hard time with it!” Nicole’s glowing adoration of her daughter and her gratitude for having her bubbled up in so many posts, like when she wrote, “What on Earth did I do to deserve this angel baby?!”

In addition to gratitude for her own life, she regularly expressed compassion and concern for others. After the 2012 election, she reprimanded people posting mean-spirited comments: “It really makes me sad to think that just because of who a person voted for, their beliefs, or what they indeed felt was the best decision for them…people want to completely turn their backs or disown people. My question is…Is that really what you would want at the end of the day?”

She posted prayers for Jessica Ridgeway, expressed outrage over the Newtown massacre, and always remembered to commemorate the 1999 Columbine shootings, which she survived—and helped a friend survive by half-carrying her out of the cafeteria. On the April 20 anniversary, she posted: “This day never gets any easier. Even as the years pass, I will never forget the horror we all went through today 14 years ago. We experienced something that will be burned in our minds forever… I pray today we all find a little peace and are grateful for what we have because it can be gone in a blink of an eye.”

On New Year’s Day, she posted this: “Happy New Year! My wish to everyone is to make every moment count and live life to the absolute fullest. Set your bar high. Don’t make resolutions you can’t keep…make life changes that matter. Here is to a great start to another year of LIFE! A gift way too many take for granted. Love you all and be safe!”

For the last five months of her life, Nicole endured surgeries and radiation treatments for tumors in her brain (after nearly 18 months of cancer-free scans, the tumors were found in June). What is so remarkable—and what prompted so many people to fall madly in love with her and become so inspired by her—was the rare combination of love, gratitude, joy, vulnerability and faith that she showed in what had become a very public experience of illness.

Her optimism was breathtaking. In August, for instance, she changed her Facebook background photo to an image of a lake at sunrise inscribed with the words, “Watch me rise,” and often posted words such as, “So thankful for this new day!!! GOD IS GOOD!!!!).” But what made her positivity so moving was that she was also real and honest. She often felt afraid and suffered from pain, and she didn’t hide or pretend. In June, when the brain tumors were found, she posted a photo of the x-ray with this caption: “I am beyond scared but I will pick myself back up AGAIN and get done what needs to get done.”

Later in the summer, she caught sight of a cloud shaped distinctly like a heart. She snapped a photo and posted it with this caption: “I needed this little sign from up above today! It is moments like this that remind me that God loves us and has a plan for everyone in the end. Things like this ‘heart’ in the sky remind me to keep fighting every day as hard as I can and that everything will be OK. EOUIAOU!!!!!”

If you’ve read researcher Brene Brown’s bestselling book, Daring Greatly—or heard about her research on Oprah—you’ll recognize in Nicole the main components of what Brown calls “wholehearted living:” embracing vulnerability as the catalyst for courage, compassion, and connection, and the core of meaningful human experiences. Brown found that those who excel at wholehearted living make a habit of certain things, from being authentic and cultivating gratitude and joy to trusting faith.

When I think about Nicole now—missing her and wishing I’d had more time with her, as surely anyone who ever met her does—I’m struck by how, in her short life, she managed to exemplify and embody the wisdom and guidelines set forth by the world’s most prominent spiritual traditions, as well as recent scientific research on nourishing wellbeing and peace through gratitude, compassion, and love.

Nicole showed us what it can look like to actually follow these maxims: “Love your neighbor as yourself,” from Jesus in the Gospel of Mark, and “Knowing that we are all destined to die, why fight amongst yourselves?” from the Buddha. She’s also an example of what a growing body of researchers have been telling us for the past decade: Service, compassion for oneself and others, and gratitude are not merely moral “shoulds.” They are necessary practices for living a happy and fulfilling life, and appreciating it.

Nicole Davis, as a mother, wife, daughter, sister, niece, and friend, showed us what is possible when you live each day as a gift to be cherished, and always remember to ask the wise question: “Death is certain, but the time of death is uncertain, so what is the most important thing?”

To read more about Nicole’s extraordinary life, click here. In lieu of flowers, the family asks that you send donations for Abbey to the Nicole Davis Fund (account #7320696268, Wells Fargo, 8500 W. Bowles Ave., Littleton, CO 80123).