Great businesses begin with a customer problem that an entrepreneur solves. We call this problem customer pain. There are many types of pain, some of which are small and some of which are large. Recognizing this difference, investors often classify potential businesses into two groups: 1) vitamins and 2) painkillers. Underneath this simplistic categorization is the idea that for a problem to be worth your time to solve, it should be a significant pain for the customer.
If the customer pain you identify is equivalent to a mosquito bite, it may be a nuisance customers are willing to live with. However, if the customer pain feels like a shark bite, customers will be urgent to pay you to ease their pain. As an entrepreneur, you want to focus on a big pain point, what we call a monetizable customer pain. In other words, a customer pain that is so big that you can monetize it, or make significant revenue from solving that pain. A monetizable customer pain represents a customer pain so significant that the customers recognize the pain, have money to pay for a solution, and will return the cold calls or emails of an unknown startup to solve it.
(See Nail It Then Scale It, pgs. 67-68; 91)