I had a good-natured argument with my father a few weeks back.
It went like this: he was slagging off a bunch of young to middle-aged women for screaming at Robbie Williams on the previous night's Late Late Show.
Fair enough I said, that is fairly odd behaviour, but so is screaming at a fella with a ball in his hand or cheering because a man playing a child's game for money scored a point.
We happened to be on our way to watch Leinster play Connacht in the RDS. We were dressed in various types of team paraphernalia, like a pair of little boys.
No way are the two comparable, he said.
Why, I asked. He gave me his reasons, mostly based on Robbie Williams being - in Liam Gallagher’s words - a fat dancer and a crap singer.
I accepted all that, but we were driving miles to stand in the RDS to shout ourselves hoarse, I pointed out again.
Replace rugby with another child’s activity - say, rounders or tag or kick the can or making jigsaws or connect four - and suddenly you begin to see how absurd the whole endeavour is.
Sport-supporting is a mad collective delusion - we tell ourselves this is important, poetic, a test of skill and manliness and all the rest of it - but it's absurd.
We're already thinking of posterity, trying to remember the experience before we've had a chance to experience it.
It's absurd just like getting excited about Robbie Williams is absurd.
And it's absurd just like it's absurd to take pictures with strangers because they happen to be the best at running fast with the ball.
I happen to like shouting at lads running fast with the ball, and I don't like shouting at fat lads singing badly. But I can't claim that one is irrational and the other is rational.
My father wasn't sold on the idea at all. That's fair enough. He's frequently unimpressed with the brilliance of my arguments.
He's not alone. Just recently there's been a flurry of articles about how fans with camera phones clamouring to click pictures of their athletic heroes is somehow soiling the ephemeral bond between sports stars and sports fans. We're mediating that relationship through the blurry, thumb-covered lens of a phone and corrupting the purity of that relationship.
Worse, it's anti-zen: we're not in the 'now', we're already thinking of posterity, trying to remember the experience before we've had a chance to experience it.
There's a degree of merit in that argument, but when you've paid a couple of hundred quid for a few hours of entertainment then surely you get to decide whether you watch it through a camera lens, a fug of alcohol, the window of a corporate box, or at home on your couch on a pay-per-view sports channel.
But more to the point, which is a greater barrier to that fan-athletic relationship? Is it some fan asking for a picture? Or is it the phalanx of PR people, media handlers, interview coaches, corporate sponsors, television rights holders, stadium security guards, Garda outriders beside buses with tinted windows, and gigantic sound muffling headphones?
Which came first? Did sport first become a massively profitable endeavour in which its assets had to be pulled back away from the fans, who were thus convinced that these were special individuals whose mere proximity was worth recording? Or did fans buy camera phones and create the massive corporate behemoth of professional sport? (The answer, like this column, is entirely rhetorical.)
And, ultimately, do we care? If I were a sports journalist - someone who made my money writing stories about fellas running fast with the ball - I'd probably stand back and not try to police the rules about what's rational and what's not: or why one act of vicarious delusion is more acceptable than another.
I've never taken a picture with a sports star in my life, but why would I lay down a claim that my way of being excited about it is the proper way, while another person's way of getting excited is totally bonkers, irrational, and some mad modern mobile phone-based obsession?
For the record, Leinster won the match and we screamed our heads off. It was all quite unseemly.