The reason people find mobile phone conversations so irritating could be down to human curiosity, say researchers in the UK.
People chat happily in a variety of public places
The volume of the call and what is being discussed play a part in making people see red, the team at the University of York found.
But in many cases it is simply the fact that we are only hearing half a conversation that drives people mad.
"Conversations only work if there is a general agreement. There is a need to understand what is said and to talk back," explained Professor Andrew Monk, director of the Centre for Usable Home Technology at the university.
"What other people are saying triggers language use and subconsciously you want to answer back," he continued.
Prof Monk was inspired to do the research after his own experiences with other people's mobile conversations.
"I was surprised at just how annoying some people find mobile conversations," he told BBC News Online.
In the study, 64 members of the public were exposed to the same staged conversation, either while waiting for a bus or travelling on a train.
Half of the conversations were on mobile phones and half were face-to-face conversations.
The conversation, about a proposed holiday and planning a surprise party for a friend, was conducted both at usually speaking level and exaggeratedly loud.
Participants were asked to rate the annoyance value of the conversation they heard on scale of one to five, as well as how much they noticed it.
Those conducted on a mobile phone in both categories were significantly more annoying and noticeable to the group than face to face ones.
The study also found that small variables such as seating arrangements could influence how annoying people find conversations.
The train passengers tended to be slightly more irritated.
"It could be because they were seated opposite to the caller rather than shoulder to shoulder," said Prof Monk.
Again this comes down to the natural way we sit when having a face-to-face conversation.
The findings could contain some interesting lessons for mobile phone manufacturers.
"Our research predicts that mobile phones with speaker phones might actually be less annoying," he said.
Other features, such as making it easier to adjust the ringtone and volume, could help make for more considerate mobile phone usage he thinks.
Personally speaking Prof Monk confesses he does not find mobile calls that annoying.
"I think it is rather nice that people are talking to each other," he said.