I saw a great saying:

No code runs faster than no code.

No code has fewer bugs than no code.

No code uses less memory than no code.

No code is easier to understand than no code.

It comes from [here](http://www.mikeperham.com/2016/02/09/kill-your-dependencies/).

And i strongly recommends [this article](https://medium.com/@yelouafi/from-callback-to-future-functor-monad-6c86d9c16cb5) for a better understanding of monads.