Some even have fancy mission statements.
Very few clearly define the "WHY" - What is the purpose or reason behind what they are trying to achieve.
This can lead to several problems:
1. It's the Purpose that drives the actions.
It's the real motivator. When you know why you are doing something and it's a powerful enough reason - you're much more likely to get the end result you're looking for.
2. Sometimes understanding the "WHY" leads you to a totally different end point or solution.
Ever have that lightbulb moment when you realized what you built wasn't what the customer really wanted? If so, You probably didn't understand why they wanted it.
This is why user stories are structured as:
As a <role>
I want <goal>
So that <why>
The last part of a user story that justifies why someone wants something is very important.
3. A lot of the arguments/ long discussions that occur during a delivery cycle are usually differences of opinion on "How" to do it.
The design, tools used, Process etc... People can get pretty dogmatic defending their position.
You can circumvent these a lot of the time by refocusing the discussion back on the purpose behind what you are doing. As long as you solve the "WHY" The How is less important.
As they say - There's more than one way to skin a cat.
Mine is better though ;)