It’s an all too common ― but incredibly annoying ― experience. You’re sitting in a coffee shop, waiting room, airport terminal or other public place, and someone nearby starts talking on the phone, using speakerphone.

Whether you want to or not, you can hear every detail, from the weekend plans to the workplace gossip to the doctor’s appointment recap. And according to etiquette experts, this behavior is not just annoying ― it’s quite rude too.

“You’re forcing those around you to participate in your private conversation,” said Nick Leighton, an etiquette expert and host of the “Were You Raised by Wolves?” podcast.

Unlike a traditional phone call, where only one side of the dialogue is audible, talking on speakerphone in public broadcasts everything into a shared space.

“This is both rude and dangerous,” said Jodi R.R. Smith, the president of Mannersmith Etiquette Consulting. “First, is it rude to those forced others to endure your own personal version of performance art. Second, callers should only be put on speakerphone after granting permission. Not all callers realize that their conversation is public and may have details they do not want the entire world to know.”