One Ohio waitress’s unfortunate story is a cautionary tale for the rest of us.

Kirsten Kelly was fired from her job at the Texas Roadhouse after she posted a complaint on Facebook about some customers’ less than generous tipping practices.

“I just said, ‘If you come into a restaurant and spend $50 or more, you should be able to tip appropriately for that,'” Kelly said, according to WTOL.

“I was mad,” the mother of one child explained. “It was a Friday night and I made $60 because I had several people that night who weren’t tipping appropriately. More than one time, people spent $50 or more and they tipped five or six (dollars). That’s not OK!” (She’s right. It’s not.)

It turns out one of Kelly’s Facebook “friends,” an old schoolmate, was one of the bad tippers in question. That person turned out to be not just cheap, but also vindictive, and she printed a screenshot of the post and took it to the restaurant to complain.

Kelly did not mention a specific customer or the name of the establishment but she was given the old heave ho nonetheless.

“They told me that I knew what I was doing when I posted that, and they would have to let me go because a customer came in [who had] printed off a screen shot of it,” Kelly said. “And they were really upset.”

The Texas Roadhouse Corporate Office told WTOL Kelly was fired for using a derogatory name to refer to the customer in her Facebook post. It is apparently corporate policy that employees are not allowed to make any mention of the restaurant on social media.

The company said, “Texas Roadhouse does not tolerate offensive language towards guests, whether it occurs online, offline or even in the parking lot.”

But Kelly’s real error isn’t calling customers names. After a night of running back and forth for a measly 60 bucks, the mother of a young son no doubt was feeling some well-directed animosity towards bad tippers. Her error is thinking social media is a safe place to vent that frustration.

Her error is mistaking her “friends” for her friends.

People on Facebook are not your friends, unless you keep it very, very limited. You probably don’t know a lot of them particularly well and you should never assume that they have your best interest at heart. People can be nasty.

A friend of mine once posted online that she was ready to pretend to be enthusiastic during an interview for a job she needed but didn’t really want. When I messaged her to say she shouldn’t be posting that on social media, she replied that her privacy settings were so high it didn’t matter. What she didn’t understand is that your privacy settings only protect you from strangers. You never know who knows who and that out of her 300 friends, there might be someone who could and would rat her out, particularly since she lives in a small town. I don’t know if any of her “friends” would do that. But why take the chance? (She didn’t get the job. Maybe because someone ratted her out!)

Never share anything online that you don’t want the whole world to know. And — since in this case Kelly probably wants the whole world to know that, provided with good service, you should tip at least 15% — never share anything that you wouldn’t want your employer, or a potential employer, to see.

Vent in the privacy of your own home, or on the phone to your actual friends – not your virtual ones.