Boss: Let's build a new system. How can we start it?
Alonso: Java! Let's write the classes and interfaces, then we connect them...
Jimmy: We could write the database. From the database we can decide what we will code...
Dev: Why don't we write first the documentation? We should write down the scenarios and the processes, so we will know better what will be on database and in the code...
(Dev is throwed out of the window)
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T-shirt: Trust the docs