My first true burnout came working at a "lifer" job, enterprise engineering for an organization everyone has heard of. It was good for a long time. Then a new manager and a change in organizational direction came at about the same time. What should have been a very fun new project instead became miserable. But I was a "lifer", and wasn't going to leave. Eventually, I got fired, and it felt like someone had cut my chains off.
The worst thing is that I wasted nine years of my career there, three in misery. And it took me a couple more years to realize that I shouldn't work for others at all, but instead should start my own company. And I'm still not to the point where I can make a living on my own product without dayjobbing. But someday, someday I'll be able to sync up my love of enterprise configuration management problems with my wish for freedom and independence.