You might be thinking that the most important thing to know about culture is that culture eats strategy for breakfast.

Now, while I believe that's true, and I have experienced it personally with both good and bad cultures, I just don't think that's the most important thing you need to know about culture.

Yes, a good culture can help companies achieve amazing things and drive long-term sustainable success, whereas toxic cultures can cause companies irreparable damage and potentially even lead to failure.

However, I believe it's more important to understand the role that leadership plays in defining and creating culture. As a leader, you have to know that you are a role model and that your behaviors will have a great impact on what your company culture looks like.

People are watching you every minute of every day, looking for clues on how to act and behave, and not just in the office but in private, too.

As Gandhi says, "Be the change you want to see in the world."

If you want your organization to be accountable, then you have to model accountability. If you want your organization to be known for customer focus, then you have to be customer focused.

But it's not just what you do that can have an impact.

It's also what you don't do!

If you don't shut down sexism, people will see it as an opportunity to practice sexism. If you don't speak up about discrimination, of any kind, then people will believe it's OK to practice it.

It's not just the words that you use either; it's also about the actions you take.

Actions always speak louder than words.

For example, I worked at one company where we talked about diversity all the time; the subject probably got more discussion time than anything else. In fact, I would say we prided ourselves on how much we talked about diversity.

The challenge was, it was just talk.

It wasn't practiced by the leader, and consequently very few of the leader's direct reports practiced it either.

This is how toxic cultures develop.

Leaders don't have to behave badly. They can just tolerate bad behavior for that to start the rot.

Just recently we have seen a spate of companies that have suffered from these types of toxic cultures, and I'm sure their leaders would say it's not the kind of behavior they exhibit, condone, or believe in.

But if you don't condemn it, then you're actually condoning it.

There is no middle ground here; there is no third option.

So while it's true that culture eats strategy for breakfast, that's only a good thing if it's not a toxic culture, and when it comes to the culture, either you're part of the solution or you are the problem.