About to board the plane, I checked my bag for my laptop and passport. Caitlin checked for her stuffed animal—an odd-looking, brown creature called “Domo”—neglecting, among other valuables, an Apple laptop, expensive souvenirs from China, and her family heirloom ring. Teasingly I shook my head and asked, “What would you do if the Domo wasn’t there?” She looked me in the eyes with an expression of terror, deliberately dramatic but also, I think, partly sincere. “I would start bawling like a baby.” she replied. To anyone who doesn’t know her, it would seem odd that she, a college student, considers a child’s toy her most valuable possession. It would seem even more odd that she falls asleep every night clutching Domo to her chest. “He’s cozy and reminds me of home,” she would say so matter-of-factly, as if no further justification were needed.

This isn’t her only childlike idiosyncrasy.

In high school we would often go on walks after school and on the weekends, strolling through the center of town and the local parks. Anytime she caught sight of a dog, she would point and exclaim, “Doggie!” Whenever we passed an ice-cream shop, she would improvise some excuse and moments later I would find us sharing an ice cream cone stacked to the brim.

She was a mystery I couldn’t quite figure out. I knew she behaved this way partly to amuse me and partly because she liked being silly. But there was something else to her youthfully capricious behavior, an element of sincerity that couldn’t be feigned. I found myself wondering if part of her defied growing up and chose instead to remain as a child, unabashed and uninhibited.

She certainly possesses the honesty and spontaneity of someone much younger. Consider me for contrast: I am an incessant planner driven by purpose, someone who feels compelled to organize even the leisure activities of a lazy Sunday afternoon: go to the library from one to two, walk around the Town Hall from two to three, go home and read from three to five. Caitlin, on the other hand, prefers to go where whim and circumstance take her. She would take me on walks without a destination, content to aimlessly wander the suburban roads and woodsy trails. As we treaded into the unfamiliar, I would grow uncomfortable, wanting to stop and figure out where we were. Looking over at her, I would see only a pair of curious, light-brown eyes. “I love wandering and seeing where I end up,” she would say. One time the path took us to a tall deserted bridge that passed over a wide marsh. It was rusted and covered in what looked like years of graffiti—thick lines of color overlapping to create a fluorescent chaos. Another time the path took us to a miniature peninsula that jutted out into a lake. There we found a forgotten bench, where we spent an afternoon talking and daydreaming the hours away. So this is what can happen without a plan, I thought. So this is what it means to adventure.

With Caitlin, rain was no longer an inconvenience; it was an invitation to go outside and see the world in gray and silver. Getting lost was no longer an accident; it was a chance to discover something new, to stumble upon a delightful surprise.

It still surprises me that we ended up together despite our opposing personalities—I always wanting to determine something’s deeper meaning, she able to appreciate it for what it simply is. And this quality, though I associate it with her youthful side, gives her unique insight in understanding her friends and family. Sometimes her mother would come home from a long day of work, mentally exhausted and emotionally frustrated. With a pained sigh and an attempt to seem happy, her mother would say, “Hi dear, how was school?” Sensing that her mom was silently being overwhelmed by a torrent of stressful thoughts about how terrible the day was, Caitlin would sit her down and bring her a cup of hot tea. “Let’s watch a crappy movie tonight. I’ll run to CVS and pick up some popcorn and gummy worms,” she would say. She knew her mother too well.

Caitlin makes it easy to appreciate those small things that inevitably escape one’s notice on any given day, dwarfed by bigger, more pressing matters. She inspires joy even in the most difficult circumstances. When I left for college, she gave me a jar filled with hundreds of colorful paper slips, each with a little note. She wrote, “Here’s a jar of random thoughts. Pull one out to make you smile when you miss me.” I remember a few long nights when I could do nothing but lie in my bed and feel the weight of her absence. I would pull out some paper slips from her jar, not expecting anything to bring me out of my misery, especially not words on pieces of paper. But of course, she knew exactly what to say.

“Take a break from the textbooks and go for a walk.”

“Don’t forget to add to our bucket list, we need awesome ideas.”

“When you’re feeling down, play some Frank Sinatra to remind yourself that you’re classy.”

Sometime later, Caitlin mailed me a copy of The Little Prince. Sitting in a quiet courtyard one afternoon, I put aside the Nietzsche tome (what I was reading for leisure at the time) and read this children’s book instead. The story about a prince from a tiny planet and his journey through the stars refreshed me, more than Nietzsche would have. I especially enjoyed the cartoonish watercolor illustrations.

A handkerchief hangs by her bedside that reads, “Life is short. Enjoy the little things.” But despite her eye for the little things, she is also vulnerable to big things. The day Caitlin received news that her Aunt’s cancer was getting worse, a glossy, unfocused look replaced her charming smile; blankness took the place of the subtle yet charismatic smile that always lingered on the corners of her mouth and the tops of her cheeks. She grew quiet, preferring neither to speak nor to listen. She passed by dogs and ice cream stores without expression, and when I pointed them out trying to cheer her up, she would only smile weakly. “What do you want to do today?” I asked. “I don’t know, I’m fine with anything,” she replied automatically. After several such instances, I realized that just as her mood can be lifted by the world, it can also be dragged down. Since the world doesn’t always present itself in an uplifting light, her spontaneous personality comes at a cost. And even when happy moments occur, they are, after all, only “little things.” A stuffed animal cannot possibly comfort her for the fact that her aunt has cancer.

Even when Caitlin retreats from the world into an inner melancholia, I want to believe that her lively side hasn’t disappeared, but that it has only been overshadowed. The problem is, nobody—not her family, not her friends, not I—can bring her out of those moods the way she can for others. None of us seem to have Caitlin’s youthful spirit that lets us see and express how comforting a stuffed animal, how delicious an ice cream cone, or how utterly exciting a dog can be. So we end up feeling helpless, able to sympathize with her but unable to console her.

Recently Caitlin had been buried by an enormous workload (typical for students of MIT), and was having trouble sleeping. Try as I might, my words had not been able to reassure her that things would turn out okay. But this afternoon, she sounded different when I called. I could once again hear signs of the characteristic energy; she spoke faster, with a certain lilt. Every so often she laughed. Caitlin described her first tutoring session that afternoon. “Since it was the first day, we went to a playground and played together so my kid could get to know me. She’s seven years old and so cute!” She talked about all the adorable things her kid did and said and how happy it made her. She sounded like herself. Perhaps no one can animate her spirit like a child can. Perhaps, just as Caitlin reminds us what it’s like to be young at heart, children remind her of the same. “My kid was so honest and enthusiastic, so much more than adults.”

As I’m writing this, trying to sort out all my memories and thoughts in an attempt to produce a cohesive and complete depiction of her, one memory keeps recurring. It’s February. Snow covers the ground—the kind that forms a week after a snowstorm, shining brightly under the sun and crunching underneath boots. We’re on vacation with a couple of friends, planning to spend four nights at a quaint rental home in Vermont’s countryside. Rolling hills, small dirt roads, and colonial houses dot the landscape. Besides the occasional smoke rising from a chimney and the infrequent passing of a car, things are still and quiet. Things could not be more idyllic. One night we build a fire in the backyard. Nestled beneath many layers of clothing, we sit close to the burning logs. After a short while our friends go inside, preferring the couch and TV. Caitlin and I stay outside, enjoying the fire’s dancing light, inviting warmth, and rustic smell. We sit there without speaking, content to gaze into the flames and listen to the crackling. I look over at her, about to ask if she wants to head in, but I stop. She looks mesmerized by the fire, her eyes holding that distinct brightness, but more intense, and accentuated by the reflection of the flames. She snuggles against me and tears roll down her cheeks.

“This is so perfect,” she says.

I feel a twinge of discomfort because I know she will lose this feeling once we go back home.

This same feeling translates into worry as I think about Caitlin in the context of college. During her time at MIT, she, like all college students, will have to face unavoidable questions about her future — an abstraction that becomes real in the form of majors and internships and financial independence. The same emotional sensitivity that allows her to delight in the little things makes her especially vulnerable to the practical matters that feel much more significant. She will certainly have to give up much of the time she would have spent getting lost on long walks and rejoicing in rainy days. But, being in an environment meant to transform students into full-fledged adults, will she have to give up her youthful spirit? I worry about whether or not this part of her is being diminished. I worry about how happy she is. I worry about how hard it is for Caitlin to be herself.

But then she sends me a handwritten letter of elegantly rounded letters occasionally punctuated by endearing smiley faces, and I am reminded that she is still the same Caitlin. Then she visits me and I see the same pair of light-brown eyes and the same rosy cheeks raised in anticipation of a smile. And somehow, in that moment, I am convinced that college cannot take this away from her, this defiantly youthful spirit that is essential to her very nature. I can imagine seeing her in four years, more mature and independent by anyone’s standards, but still the same girl at heart.

“This is so perfect,” she would say again, as someone able to see the world through the eyes of youth; someone for whom the delight of Domo and dogs and winter fires is simply too valuable to give up.