When you create a company, it will have a culture - whether it is intentional or not.
Make it a culture that you want to thrive in, and one that reflects the personality and values you want.
To be clear, having a good culture is not necessarily about striving for happiness. When you’re working 80 hour weeks, happiness is not a word you will use to describe your life. Work may take a toll on your happiness, but hopefully not on fulfilment.
Make it a culture that is scalable and that can survive beyond you. Hire people for this culture.
Hiring is one of the best definers of culture. So the Chief Cultural Officer should be part of hiring the first 50 - 100 people. This is because the initial team are the people who will define the culture as the company grows into the hundreds and thousands of employees.
Remove/fire the people who don’t reflect the culture. In the end, culture is one a very significant determinant of the success of a company.
The key is to create a company with a culture by design and by intent, rather than by default.