Over the years, I have worked with hundreds of job seekers, and I've watched scores self-destruct in rapid speed. While building a reputation takes years, it's all too easy to wreck one quickly. Just ask the college intern who gained fame worldwide after calling in a family emergency to attend a Halloween party dressed as a fairy (his boss saw pictures on the web, told him he had a "cool wand," and fired him). Or the student who e-mailed a Wall Street firm that they would be very sorry that they hadn't asked him in for an interview. (He didn't realize they all talked and that he had just voted himself out of consideration for many entry-level jobs in Manhattan.) Or United Airlines...this video from a frustrated customer has been seen over eight million times. (Many thanks to Terry Brock for tipping me off to this one.)

It takes two seconds to lose your temper, but can take months to regain your foothold. So the next time you need to sound off, pick up a secure phone and call a trusted confidant. Or write a letter using your own pen (remember that?) and then tear it up...