Culture
Culture is not something that is written in documents/slides or on walls. Culture is created during everyday moments during company building. Culture is the unspoken actions and behaviors of the team during daily operations.
Culture starts with founders. Culture is the extension of founder's behavior and personality. Don't read the careers page to know the culture of the company, talk to the founders or the team members to know the culture.
Can it be built thoughtfully? Maybe, if the founder is constantly displaying a certain set of behaviors on a daily basis.
Next time when you think about 'how do I think about building culture?' ask yourself 'how do I behave when approaching a piece of work?'