So I'm sitting in this meeting one afternoon last week and it's not too bad, as meetings go. I've got a comfortable chair, the speaker's not putting me to sleep and best of all I've got a cup of good, hot coffee steaming in my favourite double-walled stainless steel travel mug. It's sitting on the table in front of me.

That's when the guy next to me leans over and whispers, "Is that your coffee cup?"

"Yeah, it is," I whisper back.

"Because," he whispers, "I left my coffee cup at a meeting here last week."

"That's my cup," I whisper back.

"My coffee cup looked exactly like that," he whispered.

"That's my cup," I assure him, in a louder, more assertive whisper.

"You're sure?" he whispers, doubtfully.

"NO, YOU CRETIN! THAT'S YOUR CUP! I SNUCK IN HERE OVER THE WEEKEND, STOLE YOUR CUP AND BROUGHT IT IN TO FLAUNT IT IN FRONT OF YOUR FACE THIS AFTERNOON TO SEE IF YOU'D NOTICE!"

I didn't say any of that of course, but that's what was running through my mind - that, along with several Howard Sternworthy adjectives that would be unseemly to repeat.

Thing is, I spent the rest of the day in a smouldering funk. I cold-shouldered the receptionist, snapped at a couple of my colleagues - even yelled at my computer. The guy absolutely ruined my afternoon. The rest of my working day was a total write-off.

And all over a coffee cup.

I probably would have had a lousy evening too, except for something that happened on the way home. A neighbour gave me a lift, and as we were driving through town, a lout in a Trans-Am came squealing out of a side-street, went into a four-wheel drift and came within a hair of side-swiping us. My neighbour honked to warn him off.

Incredibly, the Trans-Am goon leans out his window and lets fly with a string of curses at my neighbour punctuated with an exclamation mark graphically illustrated by an upraised digit on his left hand.

I am unhinged. I am furious. I want my neighbour to stop the car so I can go over to this clown and...

But I glance at my neighbour and see that he is...smiling at the idiot in the Trans Am. Giving him a cheery wave and a big Have-A-Nice-Day smile.

"What was THAT," I ask my neighbour. "That guy could have killed us! He was totally in the wrong!"

My neighbour shrugged, still smiling. "He was probably having a bad day," he said. "No point in us gettin bummed out too."

My neighbour went on to explain that he had this theory. He figured a lot of people went through life imitating sanitation trucks. They picked up all this trash all day long - petty frustrations, little snubs and insults- and pretty soon they were overloaded. They had to find someone else to dump it off on.

"The thing I try to remember is, when somebody gets in my face, it's not about me," he said. "It's nothing personal. That person is just trying to unload his trash and I happen to be there. If I let them tick me off, then Bingo! - I've let them dump on me. But I don't have to accept their trash. I can just smile, wish them well, and wave goodbye."

And I thought: Wow. All the fights that I've been in; all the arguments and shouting matches; the scuffles and the hissy fits; all the bluster and the bullshit...

All because I imagined that someone had insulted me, tweaked my pride. What a waste of time. What a waste of energy.

In Restless Farewell, Dylan sings: Oh every foe that ever I facedThe cause was there before we came.

I first heard those lyrics in the Sixties. Took me half a century to 'get' them.

I figure I've just learned a lesson and 'm going to try and put it to good use, but first I've got one last score to settle.

I'm going to track down that guy who bugged me at that meeting last week.

I want to ask him if he'd like my coffee cup.