Post Off-Color or Tasteless Remarks
Examples abound of people being fired for racist and insensitive remarks, but some employers' grounds for firing are subtler. A Walmart employee was fired for making remarks on Facebook like, “The government needs to step in and set a limit on the kids people are allowed to have based on their income. If you can’t afford to feed them, you shouldn’t be allowed to have them!!!” An offended customer reported him to management.
A better career move: We don’t want to say you shouldn’t be opinionated, but consider whom you might offend before you post; laws on what are grounds for firing vary from state to state. As a rule, avoid subjects like race, death, or disaster. The “too soon” effect—joking about a sensitive topic that just happened—is worse in 140 characters.