And then I caught a glimpse of it. A hunched, gesticulating figure, looking somewhat desperate and needy and, I have to say, quite sad, actually. It was a seminal moment - I'd finally let happen something I swore I never would.
The image I'd seen reflected in a shop window was my own as tried miserably to deal with an important telephone call and talk politely to the supermarket checkout girl at the same time.
Well, that's a clunking misnomer for a kick off - you can never be polite to anybody with a mobile phone clamped to your lug hole, let's face it. In fact, anyone with even a hint of good manners knows that talking to somebody while listening to someone else babbling in your ear is the height of rudeness.
It was my own fault. There were a couple of people ahead of me in the queue and when the phone rang I saw it was someone I'd been trying to get hold of for days. Forgetting that this particular cashier is lightning swift, I thought I'd easily have time to finish the call before my turn to pay. No such luck.
"Can you be at the pub by six?"
"That'll be one fifty, please."
"Is ten alright?"
"I thought you said six."
"I did. It was only one fifty and.."
"One fifty? It's nearly eight."
"That's eight fifty for you then."
"Ok, see you at eight fifty."
Well, that wasn't really the conversation but the confusion and the gesturing and the pointing at plastic bags and sticking two fingers in the air and the shrugging and the whispered apologies were certainly all very much present.
It's a slippery slope. Once you've opened the door to mobile phone rudeness hell, there's no going back.
Next thing you know, I'll be leaving the device out on the table at social functions, flicking through InstantTwitFace feeds at the dinner table or screeching "I have to take this!" at regular intervals and running towards the door crouched in posture like someone leaving a helicopter.
No, I need to go cold turkey and leave the confounded thing at home for a few days with the answerphone on.
I'll get back to anyone who leaves a message. Meanwhile, if anybody needs me really urgently, I'll be in the supermarket, talking respectfully to the checkout girl.