There's a legend about a certain wealthy Wellington property developer in the early days of mobile phones. He and a friend were at dinner - or so the story goes - and the friend's cellphone began to ring. Depending on who's telling the story, the friend may or may not have answered the phone. But the next bit, everyone agrees on. The property developer lunged across the table, grabbed the device and plonked it in the nearest water glass.
Few of us would have the disposable cash to drown a phone on principle but, dammit, haven't we wanted to?
I have a friend who can't get through dinner without hiding his phone under the table and scanning Twitter every 10 minutes. He leaves sentences hanging, distracted by the text that just arrived. Phone calls can never be allowed to go to voicemail.
The worst punishment I can manage - once he has finished reading that text - is to force him to repeat the last thing I said to prove he heard me.
Surely we should by now have figured out how to use cellphones courteously. They have been around long enough.
It is a dilemma, given the point of the phone is to allow others to intrude - from a distance - into the moment we're in. But too often we're allowing that intrusion to replace the moment. I can't remember the last time someone ignored their ring tone.
These people who can't resist the siren song of their phones are called "cellphone zombies". These people walk blindly along the footpath, hunched over the little screens in their hands, eyes down. It's up to the rest of us to weave around them.
And God help you if you're pounding along the pavement and the zombie - reaching a critical point in the email - brakes suddenly in front of you.
Cellphone zombies are such a problem in Japan they've stuck warning signs on subway walls. Walking using a smartphone is dangerous, they say. Everyone is giving you "icy stares". That may be understating the peril slightly. One chap died after distractedly walking on to a railway crossing.
Back home, we're not - yet - as bad as in Japan, but our cellphone etiquette could definitely do with a tidy up. If Mrs Beeton were around today, she'd write a comprehensive book on the dos and don'ts. She'd advise you to do things like excuse yourself before you read a text. Or walk at least 3m away from the nearest person to conduct a phone conversation.
She'd tell you to end your phone call before taking your groceries to the counter. And never, under any circumstances, answer your telephone in the toilet.
But this is now a world of 140 characters so I'll keep it to one short golden rule: think about the people around you before the person on the other end of the phone.
No one wants to listen to one side of a conversation. No one wants to feel a text matters more than the story they're telling. No one wants to watch your cat video, for goodness sake.
I'll admit I sometimes laugh at snapchats in crowded elevators, or read emails to kill the routine of walking to work. But I'm going to put this golden rule into practice. And I'm going to expect manners back.
Next time my friend commits phone crime, I'll pull him up on it. And maybe, just maybe - depending on the model, age and price of the phone in his hand - I'll give it a bath.