It all depends on what you are working on. If you are Tesla and building that next big car everyone is so excited to see as a short term strategy it might work.

Working overtime on a sinking ship is rubbish. You need to rush for the nearest exit.

Note: The comment is very very irresponsible on part of Mayer. Yahoo! anyways is not a preferred employer these days. How is she supposed to hire the best talent with these kind of statements ?