Growing up, David admired his charming and gregarious older brother for his natural ability to inspire loyalty and camaraderie. John always knew the right thing to say to make people feel comfortable and engaged, easily earning their trust and affection.

“Socially,” David would later say in his book Memoirs, compared to his brother John, “I felt like a misfit.”

It would’ve been a typical sibling rivalry, except David happened to be David Rockefeller, grandson of esteemed oil baron John D. Rockefeller. He longed to live up to the Rockefeller name and its outsized legacy of business and philanthropic success.

“John, of course, had the name,” David wrote. “Of all the children, John was the most like Father in personality; he was hardworking and conscientious.”

These feelings remained over the next decade, becoming more acute during his military service in World War II. As an intelligence officer stationed in North Africa, he began to realize that others depended on his ability to forge relationships and work well on a team.

When David returned from overseas, he dedicated himself to knowing–and being more thoughtful with—people. He started keeping meticulous notes on every person he met to become a better listener, colleague, and friend, resulting in a manual system predating the convenience of personal computers.

David went on to rise through the ranks at Chase Manhattan Bank, eventually becoming its chairman and CEO, all while managing and furthering his busy social obligations as a Rockefeller—a shadow of his former, socially awkward self.

“He was able to pick up as though he had seen you the week before," James Wolfensohn, a friend and former president of the World Bank, told the Wall Street Journal in 2017. “It was because of this extraordinary record system.”

By the time he passed away in 2017, David had spent over 50 years collecting 200,000 notes on over 100,000 people, all written on standard index cards. He later ascribed his success in business, and in life, to the system that valued serving others before himself.

The beauty of the system was not only that everyone received a card, regardless of social standing, or that it was so extensive it required its own custom machine. It also confirmed Rockefeller’s early instincts, forcing him to focus on the exact personality traits that he lacked and identified in his older brother and father: their attentiveness to others, their dedication to service, their hardworking nature.

Their conscientiousness.

More than extroversion or intelligence, conscientiousness is the single most explanatory factor of happiness, wealth, and success, according to extensive recent research. Conscientious people tend to be organized, responsible, and plan ahead. They work harder when faced with challenges and on average report higher levels of happiness.

It would actually be nice if there were some negative things that went along with conscientiousness, but at this point it’s emerging as one of the primary dimensions of successful functioning across the lifespan. It really goes cradle to grave in terms of how people do.

Simply put, being thoughtful pays dividends and, even more remarkably, it’s learnable. Conscientiousness is one of the most malleable personality traits.

Unsurprisingly, many people list it as a New Year’s resolution, hidden within the narrower set of qualities and behaviors it enables — being more disciplined, more generous, more punctual, more efficient, more organized, more considerate.

Almost all successful people naturally identify the importance of conscientiousness in their lives and careers. They develop their own method of tracking follow-ups and remembering their day-to-day interactions, whether it’s a 200,000-card system or notes apps, calendar apps, sending themselves an email, hiring assistants, or writing to-do lists.

They create band-aids, personalized, ad-hoc systems to remember the most important parts of their careers and their lives: other people.

Personally, we grew tired of our endless toggling between apps, of the scattered, slapdash nature of maintaining close personal and professional contacts in notes apps and Excel files, email and text messages. We wanted a more streamlined and thoughtful approach for keeping in touch with our ever-growing network. And after searching and searching for something better, we built it ourselves.

We subscribe to the idea that being thoughtful and helpful with people is still too difficult. It’s something we all know intuitively. To achieve more, to be more successful, to be happier, we need to start thinking about others first.

Clay makes that a heck of a lot easier.

— Matt & Zach