An excellent culture might be perceived as a form of "perfection". At what point does one draw the line, point and say: "Now we have achieved an excellent culture." Once the line is drawn, the excellence achieved, a few will be looking over their shoulder more worried about the achievement of culture vs. the people, purpose and profit of the organization.
Do you look around an organization you lead, are a member of or work for and ask yourself "how long will I put up with this?" If so, you will not find the answers internally. The answers are external and yes, you can have an impact on the culture at almost any level.
Defined: Organizational culture is the behavior of humans within an organization and the meaning that people attach to those behaviors.