Culture: The assumptions and habits of a group. Your organization's culture (whether your job, church, family, or group of friends) is the unconscious thinking (the assumptions) and unconscious actions (the habits) of the majority of the people.
Your culture promotes some people to power and marginalizes other's opinions. Your culture makes some decisions happen fast and makes some complicated and slow. And all cultures have this impact--not just good or bad cultures. The question is which people and decisions are impacted, not whether people or decisions are impacted.
The first step in shaping culture is moving it from unconscious to conscious awareness. Before I can shape my culture, I must be able to truly see my culture. Too often it's like seeing your own posture the way others do. You have to do extra work and use extra tools to get a clear look at yourself. If you don't understand what's going on and why, you can't change it.
Can you clearly describe the culture of your organization? For example...
What topics does the leader NOT want to talk about?
Who are the heroes?
How is conflict viewed?
What exactly does "on time" mean? 15 min early? Right as it starts?
What roles are seen as most and least important?
These are just sample questions to get you started. Getting clear on you culture might require a lot of thinking. But it's so very worth it. The culture you have is already shaping everything else.
Being ignorant of your culture doesn't keep it from shaping you. It keeps you from shaping it.