Very quietly last month, Path, the social media network founded by Shawn Fanning (Napster) and former Facebook executive Dave Morin, closed its doors after 18 years. What differentiated Path in the early days was that it limited the number of users’ connections to the seemingly arbitrary number of 150. Adding any additional contacts required that the user delete others to make the room. Morin’s argument was that “We want to connect you to the right 150 people.”

Gore founder W. L. Gore also gravitated to this magic number of 150 — limiting colocated teams to 150 people before moving any overflow to a new property. Gore’s reasoning was very similar to that of the founders of Path: To maintain stable social relationships at any given time, the number of connections needed to be limited to 150. Malcolm Gladwell refers to this in his best-selling book, The Tipping Point: How Little Things Can Make a Big Difference.

The number 150 (in fact, 148, to be precise) is actually far from arbitrary and stems from cognitive research done on primates by the British anthropologist, Robin Dunbar. Dunbar found that the group size of primates was a direct function of their relative neocortex size — which meant that, for an individual of a group any larger than 150, healthy social relationships became too difficult to actively maintain and manage.

If you extrapolate Dunbar’s findings to include brands, as Dunbar did from primates to humans, you begin to imagine that a brand could effectively take the place of a human relationship in that limited cognitive space. Melvin Brand Flu, partner and director of strategy and business design at Livework, calls these slots “target entities” and holds that “the 150 relationship slots don’t (all) have to be human.”

Jamie Anderson, the SVP of experience at ICF Olson, agrees and points out that “the energy we spend with the brands we love” easily replaces the relationships we have with some people in our lives. The time we spend visiting a website, strolling through a store, or watching or reading content from one of our favorite brands expends not only energy but time and cognitive capacity — both of which are acutely limited.

This begs the question: Should a brand try to create a deep relationship with every potentially addressable customer? And if not, how does a company determine which customers they should have deep relationships with?

Customer experience (CX) professionals and marketers can benefit by recognizing that not every customer will (or is even physiologically able to) love your brand as much as you wish they would. As we pointed out in our CX predictions report last December, successful companies are now serving a narrower set of customers more deeply. This starts by going deep into the customer data and identifying the most ardent fans. Repeat customers are valuable customers. Prioritize and nurture these high-value relationships. By narrowing your scope, you can reduce waste, personalize better, and take solace in the fact that you really don’t have to get every customer to love you.