One company, one culture.

This myth originates in management consultants and scholars adopting literal interpretations of early 20th century ethnography on so-called “primitive” societies.  Modern organizations of any size are complex societies made up of many cultures. Thinking of a corporate culture as a single, tangible entity is usually the product of ideology, not culture.

The leader creates the culture.

Leaders have something to do with culture, of course, but it's not that simple. Cultures are not mirrors of the CEO or founder's personality or values. Leaders need leadership teams and a committed workforce to put in place the business practices that proliferate and sustain cultural knowledge. 

Culture is what we value.

Managers believe they can gain leverage over the workforce by substituting one set of values for another. But it is hard to impose values unless they pre-exist in the organization (e.g. getting a software engineering organization to buy in to engineering-oriented values is much easier than getting buy in for industrial manufacturing values); values are expectations, not behavior; and people don't always behave according to what they say they value. To reduce culture to values is to grossly oversimplify something highly complex. 

Culture is how we treat each other.

How employees feel and behave might be an expression or enabler or reaction to some underlying aspect of a culture, but it's the tip, not the iceberg. Employee attitudes and behavior is a reflection of entrenched and pervasive business practices and the dominant cultural logics that structure them. So better benefits, free food, or communications training won't move the needle.

The right culture will drive business performance.

If true, then why do "toxic" cultures exceed Wall Street expectations? This myth was debunked decades ago when a significant number of firms lauded for their cultures later went out of business or saw significant earnings declines. Managers hold on to this myth even though establishing causal links between culture and business outcomes has never been adequately demonstrated, and even though much of the theory and methodology for doing so is deeply flawed. To reduce culture to the independent variable in economic performance is simply shoddy or myopic science.