Just today morning in Tallinn a whole wall of a brand-new building just fell down!
Update: The building was not new and it fell because there is a road reconstruction very nearby.
This made me think that automated unit-tests can save at least your soul.
As soon as there is a bit more complex code to be programmed it's very tempting to get it first working without using the glue or cement to nail down the foundations of the code.
By cement I mean automated tests, of course.
The implementation you write is only a set of bricks. Which can be used to build a wall, of course.
To really keep them together and ensure that they STAY together, you need to write tests.
Let the Sun Shine and Tests Run!