There's that section about how Meta executives got drunk on an airplane. And the only thing that happens is they sing karaoke. There's nothing inappropriate. They're a bunch of boring nerds.
The author thought the people she was working for were Really Special People and that by extension she was a Really Special Person. She gets very upset when she sees that are just Ordinary People and that by extension she is just an Ordinary Person as well.
And how could she be just an Ordinary Person and so sad/stressed at the same time?
Offering a contrasting opinion: I enjoyed the book, and I don't think the author comes off as "sour grapes" at all. Instead, she joined Facebook out of an unwarranted and frankly silly idealism that FB could be a transformational force for good in the world. Even she admits this in the book. However, Meta execs came off far worse in this book than they already seemed, and that's saying a lot. Mark's indifference to Meta's impact on elections was horrifying to read about. And the chapter "Lean In and Lie Back" put a deeply disturbing bow on all the awfulness about Sheryl Sandberg.