Of the group who use your product or service, there is probably a sizable subgroup that doesn't choose you over the other guy as much as they allow others to choose you for them. It's why some marketers place such a heavy emphasis on "influencers". They drag many others along for the ride.
When you are on the good side of the influencers, things are dandy. Fail a few times with the influencers and you lose not only their business but those who pay close attention to the things they do. Much is at stake.
Do you know who the influencers are? Probably, but you can never know the full roster, especially those who are coming on the scene.
Its best to treat each customer as if they have a hundred future transactions in their pocket. You just never know.