When you're startup is fortunate to have paying customers, it's very tempting to evolve your product based on the feedback you receive from them.
After all, isn't that the best practice--to iterate based on customer feedback?
The problem is, if you base what you do solely on the feedback that comes in from customers, you're probably building exactly the wrong product.
There's an awesome World War 2 story (possibly apocryphal) that illustrates why. Statisticians checked fighter planes after every mission, and recorded all the damage they could find. Pretty soon, they had a chart of the fighter that showed that the damage was concentrated in specific areas.
Most people's gut reaction would be to add armor to the areas that took the most damage. But that would be exactly wrong. The information the statisticians were gathering didn't show which areas were most likely to get hit...they showed which areas were most likely to get hit without destroying the plane.
The smart designers instead added armor in all the areas that weren't marked on the chart, reasoning that these were the actual vital areas, where a hit wasn't survivable.
The best customer pays your startup a ton of money and never calls customer support. The worst customer pays your startup very little and constantly calls in with problems.
Waiting for customer feedback to come to you is like armoring the bullet-riddled areas--it feels good to do something, but it might actually harm your chances of survival.
Instead, be proactive--identify the people who are your best customers and initiate the conversation. Those are the customers you should be designing your product for.