One is the critical person, who is depressing and painful to work with and gets furious at the slightest bit of poor service.
A type of rational customer, who is easily receptive to his dissatisfaction if you can give a reasonable explanation for it.
The third type is, the meek and tolerant customer. Even if you don't serve him well, he won't aggressively give you his dissatisfaction. We need to serve the most good is the third kind of customer. We have the most people of this type in real life. They will not use the most mouth to speak, will not make protests or suggestions, but to speak with their feet. Making a website is also the same, if we do not focus on those hidden behind the experience of the users who do not speak, they quietly leave, not even a critical opinion will not leave, this is the most terrible.