Delicate situations at work are best handled privately and politely: No one loses face and you minimize the potential fallout of reputation or morale. People are generally more receptive to constructive criticism and discussion when approached with quiet civility. What's more, successfully handling your own interpersonal conflicts maintains your reputation with your supervisors, who may resent you pulling them into the affair or feel obligated to escalate it further if you do. If you handle the situation online, however, you risk blowing it out of proportion or even expanding its scope office-wide.
Knowing when to take matters offline also applies to expressing your interests and opinions. Fair or not, people judge us according to the image we put forth. In the real world, a boss, coworker or client might think less of you or even silently harbor ill feelings toward you, because of your clothing, a bumper sticker on your car or even a coffee mug slogan. How much worse, then, might they react to you joining a sarcastically named group on Facebook, or stridently expressing a tactless or divisive attitude on a sensitive subject? Unfortunate decisions and foul moods are transitory, but Internet postings are forever.