Some jobs just rely on attracting and retaining people with no boundaries and no ability to set them. Startups are great at this. They foster a sense of community between the workers and then understaff/overbook the team. When the invariable crisis rolls in no one even has to tell people to work until 5 am. They just do it because no one wants to "let down the team".
My last job I was at least the fourth or fifth person to break down and cry at work. Plenty of those happened in meetings where the boss man was present. They just quietly get replaced and that's that. Burn em and churn em. Never shows up on the ledger and everyone writes it off as a crazy one-off situation.
Then oh gosh a big deadline hits and we're down a person, better show off what a team player we are and make sure we hit the deadline.