As a founder, I have been there myself and learned the hard way.
So, I don´t blame you.
Let´s go through the process:
We think of a business idea. We get excited!
We talk to (a few) potential customers (aka friends & family).
We are confident. WE KNOW WHAT THE MARKET WANTS!
We can’t wait any longer. We are too excited!
It is simple. It is obvious. We need to start building.