Do you discuss personal matters with your co-workers and reveal complicated details that could later not serve you well?
It's kind of hard sometimes not to. After all, these are the people with whom you spend at least eight hours a day, five days a week. You're practically living with them - you spend more time with your co-workers than you do with your own family.
There are several reasons for not sharing personal information. You may not want to burden your colleagues with keeping a secret, or not trust them with doing so. By the time you find out someone has shared your story with the wrong person, it's usually too late.