Why is a mission statement important?

Once we've defined your vision clearly then you can work on the practical, 'how do we do things day to day' aspects and bring the whole company into alignment with it.

I like to use the analogy of an old ship with oarsman and sails of the sort used in ancient Greece. Without plotting a course the ship has no clear direction. 

It's only once the ship's captain has clearly defined the direction and shared that with the oarsmen and crew, that everyone knows what they need to do.

Those that are in alignment with the direction, i.e. those who want to go there and have the right attitude, can all start to pull in the same direction.

Moreover, the people or parts of the ship that aren't fit for purpose, that aren't in alignment will then become clearer and can be developed, replaced, or upgraded.

With a clear vision, the day-to-day can be easily defined; processes, values, structures, and rewards that all align to the achievement of it.

The result is an entire organisation or department where everyone and everything is working as an efficient unit, together and united towards a common goal.