One of my good friends I used to talk about a lot here in my Austin days was fully vested in his company several years ago, which included a big chunk of company stock. Shortly after that they went public and the company's worth exponentially accelerated rather quickly. Then they laid him off. He wound up selling his stock, which had, in a matter of weeks, become worth a couple million. He took a nice tax hit for it, but overall he didn't regret it. And a piece of it helped float him along, as he wound up being out of work for well over half a year.
I guess if you get laid off, it's nice for them to hyper-inflate your net worth on your way out the door.