Culture is what you won't tolerate.
If you don't tolerate tardiness, then when people ask your team about the culture they will say things "you can't be late here" so long as you show that you don't tolerate it.
If you tolerate tardiness, no one will explain your culture as punctual.
When you're building a culture think about the select few things (too many and they can't be remembered) like direct feedback, *A players only, speed and kindness not to be confused with weakness.
*A Player Definition: 90% likely to achieve outcomes that only 10% of applicants for that role could achieve.
A players seem to be the most immutable thing in all of startups so just get that one right if you're gonna get any right.