She remembers the dirt roads in Phnom Penh, the muddy water after the rain, the brown-outs and, more vividly, the children.
"They were playing in the street. I couldn't see their mothers, maybe because the women were selling things in the market elsewhere," said Mrs Chan Yuming, who first went to Cambodia with her church group to do community work three years ago.
"You wonder about the future of the children and you feel for them. I know it sounds cliched, but I really wanted to leave something there that would have lasting impact," she said.
Mrs Chan, a 28-year-old newsletter editor, has since gone back every year for two weeks each time. Here group aims, among other things, to build a medical clinic and set up English classes.
It may not seem like much, considering how much more needs to be done but, she said, empathy and action, at least, are better than hopeless resignation.
When I was 16, I had a history teacher who was a union activist. His office was decorated with a motley of bumper stickers. I never thought much about them. To me, they were just left-overs from his hippie days.
There were statements like: "Subvert the dominant paradigm" and "Think globally, act locally," and this one: "If not me, who? If not now, when?"
Growing up in a land of plenty, in a time of plenty, the post-baby-boomer generation has, more than once, been called spoiled. And, I must admit, I am -- along with most of my peers. We grew up with all of the privileges and none of the setbacks.
Racial riots and instability exist, for me, mostly in history textbooks and in the memories of older relatives. As a child, I vaguely remember adults discussing the oil crisis of the '70s. When the recession hit in the '80s, I was still tucked safely away in school. I started work in a booming market, riding the rich economic wave that employers see as part of the reason for high turnover.
All right, so we live in an intensely competitive environment with an increasingly high cost of living. And we have to work harder than our parents probably did to get the same things. Perhaps that is why many of us are starting to question this quest for upward mobility and looking to chase something other than the 5 Cs.
Finally, we're starting to define ourselves by something other than our work and our achievements.
Mrs Chan's friend, Mr L. H. Wong, who has also done stints in Cambodia, said over coffee that he gave up a higher paying job for a more regular one so he could have a life.
And that included doing more for other people.
"It's nothing noble, I just want to give back as much as I have been given," said the 33-year-old. "At the end of the day, I want to have lived for more than just my job."
And boy, is there a lot of live out there. Even in our own backyard, there is a lot that would be much more convenient to ignore.
One advertising executive who grew up in a middle-class family remembers his first encounter with poverty as a volunteer at a social service centre. He saw, for the first time, families of six to eight squeezed into one-room flats; children caught up in the cycle of their parents' drug or alcohol addiction; old people abandoned by their children; a child who had to look after his intellectually- disabled parents.
"I never expected to see this here," he said. "Everybody else in Singapore has a certain standard of living, and here's this group, totally forgotten.
"And I thought: `Well, if everyone else has forgotten, maybe I shouldn't forget'."
If anything, going outside of your own safe world reminds you that your own problems are small.
It also reminds you to take nothing for granted.
A few months ago, I was at a social service centre helping a social worker who was conducting a class. My job was easy: I was one of a group keeping an eye on the kids, some of whom were bouncing off the walls with hyperactivity.
The children were playing an auction game. The social worker gave them monopoly money to bid for various things: a pretty wife, a big house, good friends, intelligence, a good job.
Most of the children apportioned their money so that they could buy a spread of goods -- until the boy sitting next to me raised his hand to bid for "a happy family" with his entire wad of cash.
"Don't you want to use the money to buy other things?" I asked, when he was handing over his stash.
Hugging an oversized teddy bear, he looked straight at me and said in Mandarin: "No. Wouldn't it be nice to have a happy family that didn't fight all the time?"
I never looked at my own sibling skirmishes the same way again.
But really, why should we bother to do anything about anything? It is easy to feel hopeless. It is even easier to sit back and say there is nothing we can chance, then feel sorry for ourselves, for everything that is going wrong in our own lives.
Of course, we can just say that nothing one person does will ever be enough. God knows, it is a messy world out there.
We could leave it to other people. And then complain that change comes too slowly, or not at all. Or we could just say it is not our responsibility.
Or we could say we will wait till we are more established in our careers before we do anything; and after that, wail till our children are just a little older; and after that wait till they get married and get out of the house; and then wait until we are retired; and then we can tell ourselves that we are too old and tired to contribute.
Someone in his 50s once told me that everything goes so smoothly here, there are no causes for the young to fight for.
But this is not about big causes, or about fights. It is about believing in something and leaving a mark behind, however small. And especially since we are the generation that has been given all the breaks: education, exposure and, for many of us, a certain amount of affluence.
Besides, if we do nothing all our lives, what should we have lived and stood for?
Now, more than ever, that slogan from the sticker in my history teacher's office keeps echoing in my head: "If not us, who? If not now, when?"