Friend of mine just got laid off from 15 years at google, he's in his mid/late 40s. He's started to learn about embedded systems, hardware controllers, he's playing with haskell and erlang and doing work he's never done before, actually very far from webscale DB architecture, he's the most happy i've seen him in his life, he's following his curiosity and he's like a pig in mud.
After 15 years at Google he’s most likely at a point where he doesn’t have to work for a living anymore, and still afford a comfortable life for his family. I imagine that’s a big part of his happiness.