1. Lack of success. All too obvious? Yes. But egos are built on success and are just as easily crushed by failure.
2. If you are a heterosexual like me there is of course the opposite sex. We are told that everyone loves a winner.
3. Starting over again. No one wants to do that.
4. Coming to terms with what went wrong. No one wants to do that.
5. Figuring out where to go from here.
6. Being thought of as a nowhere person.
7. Not being treated well by those who were banking on your success.
8. Not having learnt enough from some past failure.
9. Being blamed for someone else's failure if the two are connected.
10. Finding that it was a sociopath (they do exist in the business world) who led you down the wrong path for their fun and profit. I think there was a bit of that going on with Enron years ago.