we don't apologize for working hard. we're a startup trying to make it in a competitive business.
Past a certain amount of time, you're spinning your wheels, doing bad work you'll have to clean up later, and pushing yourself towards an early burn-out.
It's unhealthy, non-sustainable, a bad cultural precedent.
If there's no other choice, then do it -- we all have. But don't be too proud of it; it's not something you want engrained in your culture.