In 2004, American pro football wide receiver Terrell Owens was welcomed into the Philadelphia Eagles locker room. The new addition to the team was warmly embraced by star quarterback Donovan McNabb, and the dynamic duo led the Eagles to a conference championship and their first Super Bowl in 24 years.

It seemed the beginning of a beautiful workplace friendship, until …

Owens hinted that McNabb was to blame for the team’s Super Bowl loss. His agent began demanding a new contract for more money, and Owens bristled when McNabb failed to pressure the team on his behalf. Owens declared that with another quarterback at the helm the Eagles would be undefeated. After McNabb suffered an injury, Owens questioned the quarterback’s courage. Owens began fighting with other teammates, and created so much dissension in the locker room that the team’s camaraderie unraveled.

Citing conduct detrimental to the team, Head Coach Andy Reid suspended Owens for four games, then deactivated him for the remainder of the 2005 season. Following the season, Owens was released. The problem was gone, but it took the Eagles—especially McNabb—time to clean up the wreckage.

Though the teams that subsequently signed Owens knew what they were getting, when “T.O.” joined the Eagles, McNabb had few hints of the damage his new “friend” might cause. He was as much in the dark as you are when meeting new people in your workplace. So to avoid getting burned when friends turn out to be “frenemies,” take this advice:

• Pretend you’re rich and famous. No, that doesn’t mean wearing shades when you’re inside. It means pretending that anything you say today may wind up on TMZ tomorrow. The Oprahs and Brad Pitts of the world have to be guarded. They can’t divulge the intimate details of their lives to every casual acquaintance they meet because they know people are willing to pay big bucks to get that information. They have to be selective about what they say and to whom. Though no one may be willing to pay for info on you, that doesn’t mean some people won’t drop it for free if it makes them seem knowledgeable or important, if it builds them up at your expense, or even just for the heck of it. So in a work environment, be as guarded as the stars.

• Tiptoe around touchy topics. You’re sitting with a group of work friends and one comments on an absent colleague’s appearance, relationships, religion, politics, finances, etc. Don’t go there! You can a) be bold and suggest changing the subject, b) subtly express your discomfort by excusing yourself, or c) just sit there, keep your mouth shut, and hope you’re not later found guilty by association. But don’t start discussing another associate’s personal business—or your own—on the assumption that it won’t go further. In all likelihood, it will.

• Look for the cone of silence. You’re standing in a crowded elevator at your workplace, whispering about your idiot boss with a friend you know you can trust. How nice that you’ve found a trustworthy office friend! Now look around. Do you see a cone of silence separating you and your trustworthy friend from everyone else in the elevator? No? Then shut up! Why do we think that if we’re away from our desks, we’re out of the danger zone? So what if you don’t recognize the other people in the elevator or at the adjoining table in the cafeteria? That doesn’t mean they don’t know your boss or won’t repeat your comments to someone who does. Conversations are only private when they can’t be overheard by anyone else.

• Learn from the burned. If you inadvertently trust the wrong person, take a lesson in recovery from McNabb. Despite having to deal with T.O.’s sideline tantrums, his team’s on-field inconsistency, his own plaguing injuries, and the media’s constant demand for comments, McNabb managed to rise above it all. He didn’t scream or sulk. He just quietly answered reporters’ questions, did his job, and proved his worth on the playing field. In time, he was again contending for a conference championship, while Owens was wreaking havoc with another quarterback in another locker room. If you keep your cool, hold your head high, and focus on doing your job, you’ll bounce back. And like Owens, your nemesis will move on to “befriend” someone else.