It's hard not to be negative in the Great Recession. Unemployment is insane (actual unemployment much higher). Greece may destabilize the Euro for a decade. Wall Street appears to be run by spoiled children. You're not sure what to do with your career, and hope you can make ends meet, let alone live your dreams.
On top of all of this maybe you're unemployed, or your city or state are in the dumps, or your friends are facing career meltdown.
It's hard not to be negative. It's hard not to rant or white or get angry, it's hard not to vent constantly because there's so much built up.
And for the sake of your career, I recommend you be bloody careful with your negativity. Why? Because Negativity in all its manifestations, from the screaming tearful rant to the mopey self-absorbed withdrawal, can poison your Network.