Simple is better than complex 

Simple design means simpler code, both to write and to maintain. A simple design requires less time to be explained to our costumers or to new designers who will work on it. This is the reason why we always choose the simpler way among the ones that can work.

Correcting a bug in an already written code is twice more difficult than writing it 

So, if a developer writes today such a complicated code that even he finds hard to understand, how will he repair it tomorrow, when problems arise?

We try to keep things as simple as possible. 

And as long as possible: we do not add features before they're agreed upon, we do not complicate designs for future choices we will never make. And we have gathered experience in this respect: surely, planning a good simple design is terribly .. complex!