The short answer: I was denied tenure at the University of Massachusetts-Amherst in 2008. It wasn't fun, it wasn't a surprise, and it wasn't the end of anything really, other than my employment at UMass. All my graduate students were able to get their degrees. It was a big hit to my ego, and a big reality check: I was not made for a life-long academic career. At that time, and after feeling like dirt for a while, I started consulting for the biotech industry and loved it. In 2009, I moved to Spain and took a job at a start-up, which in turn went belly up. Now I run my own synthetic biology company in Madrid and enjoy a different take on experimental science. I miss teaching, though.
The somewhat longer answer: it felt like being the victim of a mafia hit by members of your own "family": the same people that yesterday invited you to their kids' birthday parties and pinned awards on your lapel are today pulling the trigger. I was treated with exaggerated courtesy, and I could tell some people were truly afraid I could go psycho and do something terrible. It felt unreal, 15 years of a successful academic career ending like that. It also revealed a lot about the character of my colleagues: some avoiding me as if I had a contagious disease, others offering warm, friendly hands. Some even tried to show me the dark aspects of tenure, which to me sounded like a wealthy person's complaints about wealth.
By the way, it is worth saying that the University did everything right, at the Departmental, College, and University levels. There was no monkey business in my case. In the previous years, the Dept and the School really helped to lighten my load and facilitate research and grant writing. When the moment came, the Department Chair came to my office almost in tears to explain to me his negative vote, and I knew that without his support, it was a lost cause. I had a long time to prep for the final decision. The Dean took me for lunch when the dust settled to offer his support.
Personally, it helped to push me into a mid-life crisis that had been looming for a while. I was depressed and withdrawn, everyday tasks became titanic work, and I could see the worry in my students' eyes, for me and for their careers. I started therapy, which helped. I tried antidepressants, which didn't. I was advised to take legal action, which I didn't. I guess deep inside me, and despite 16 years of preparation, I knew that it was not my scene. But I was too deep into it to face this reality, and the conflict really took a toll on me.
Little by little, and helped by my great Department colleagues and a few close friends, I started shaking the blues off and tried to find comfort and enthusiasm in other aspects of my life. I faced the ultimate question: would I have given tenure to myself, objectively? The answer was clearly no. When I made peace with that reality, I started planning a future. I realized that I was lucky: no kids, relatively young (41), and with a good track record. I got married and I moved to Spain, a country I've always loved.
It took me a while to understand that anyone who makes it to a tenure-track position in an American research university has self-started so many projects and amassed such a network that starting anything new is actually quite easy. Good luck to all tenure-trackers out there! And cheers to the tenure survivor, one way or another.