I did not say that I'm slow due to this or not agile.
But I will not build a sync feature and not having alerting if it fails.
I will not write nee Features and will not think about a proper index.
If you do it right and actually learn those things from an early point those things become obvious.
And yes there is also that believe that a bug in production costs 10x what it would cost to find while developing.
Yes I'm aware of the fallacy that a manager might praise you if you are fast and accepts bug as a common normal thing.