What was one mistake you made?

As entrepreneurs, we are doing many mistakes on the way and this is how we learn and evolve. Mistakes are natural part of our journey, i believe. Together with this, lets share our mistakes and learnings from each other to grow faster together. Let me start first; finding potential users is very hard and this led me to the mistake of "not talking enough" to our users while setting direction to our product. In order to stop doing this mistake, currently i am tracking data about how many users we talked per week and trying to improve that number.