I worked at a YC company a couple years ago. They did not say they were 7-day-weekers, but the culture encouraged it.
There were 2 planning meetings per week, one on Thursday and one on Monday. So if you set a goal on Thursday… you should have it done by Monday.
A young manager there would work 24/7, stressing the hell out of most people who worked with them.
Of course, things would be broken that required weekend death marches.
The thing with startups is, it’s easy to default to this. After all, to the founders, this is the most important thing ever. It’s their ticket. And they try to make it seem like your ticket as well (it’s not).
But smart people don’t work like this. Smart thoughts don’t come out of exhausted brains. It’s a meat grinder for no reason. It’s sadistic.