Knock it down to 14h, and I can think of 2 people. I worked for both, and both fell into the category of having moved to the US from another country. My career took me elsewhere, but they were both great to work for.
It's worth watching this talk from the Leading @ Google series - https://www.youtube.com/watch?v=tke6X2eME3c
The short version is, despite the information-age, we still think about this stuff in an industrial-age terms; that productivity is directly proportional to time spent. In fact it's highly non-linear for most forms of information-age value creating activitie.
As an anecdote, when I first moved abroad I was single and didn't speak the local language (Dutch) so I didn't really have any incentive to interact socially outside of work and I ended up spending way too many hours in the office but just about managing to do my job competently because I was pretty sad and demotivated all the time and often doubted my decision to move abroad.
No, they held US citizenship. They were just hardworking immigrants.
I'm the grandson of immigrants, which makes me positively lazy by comparison. I pretty much have to knock off after 12 hours these days.