I had chocolate to the right of me, coffee to the left of me and I was happily logged onto the free wifi, ready to catch up with the world on my iPhone, when it happened.
And I wish I'd brought my ear plugs. Not to drown out the Lords of the Flies background noise of this aircraft hangar of hell. That I can cope with, having developed selective hearing during four years of motherhood.
But to turn down the volume on what is one of the most irritating practises of modern parenthood – the bellowing of praise by megaphone mums and dads at their poor children.
"OH, DARLING, MUMMY IS SO PROUD OF YOUR EXCELLENT SHARING. SHARING IS CARING, ISN'T IT!" boomed a mother to the entire building.
Happily, both kids completely ignored their mothers and shot off to play so the rest of us were given an interval until the next toe-curling performance.
But when you're in a playgroup, on a bus or in a café, there is no escape.
Mum-of-twin boys Sally told me she stopped going to a parent and toddler session because she couldn't stand any more of this ear-splitting encouragement.
"It's the competitiveness that got to me. As soon as one of the mothers had bawled at her little one for 'playing nicely', it would set off a Mexican wave with another trumpeting at her 'clever' child for building bricks or dressing up or whatever she was doing," she said.
"One after the other, they'd join in and I found myself beginning to join in when I am not that kind of parent – it's like it's contagious. It also made me doubt my own interaction with my boys, which I later realised was perfectly OK, so I didn't go back."
Worse, some roar their approval when what is really needed is a hissing rebuke.
Mum-of-three Corinne said: "I was at a playgroup the other day when a mum glossed over her son's tantrum after he tried to snatch a toy he wanted. Rather than tell him to wait his turn, she publicly applauded his 'good communication skills'!"
So why do some feel the need for this at-the-tops-of-their-voices running commentary of stupid? Isn't it enough to give your child a quiet word of praise? There is simply no need for loud parenting.
Unless, oh my goodness, it couldn't possibly be because they want to be heard, could it?
To show how good they are at parenting?
To demonstrate they're better at it than us?
To prove they've read the latest 'how to' guide?
To convince themselves they're doing a good job? (Sorry, a "GOOD JOB".)
I understand why loud parenting has permeated parenting: it's a huge industry, there's money to be made and judging by the depressingly pervasive headlines of abuse and neglect, there are some things which need spelling out, just to be sure we all get it.
But the trouble is, those parents who should trust their perfectly acceptable instincts worry they may not be up to the mark and end up over-compensating by shouting "WELL DONE, SWEETIE, BRILLIANT BREATHING".
Maybe there's some guilt involved too; too much work, too little sleep, and head-jerk, blimey, we just drifted off there, what have we missed, wonder if anyone's noticed, quick, give the kids a slap on the back for something to show we were concentrating.
Some will say all this child-cheering is turning our kids soft. Chance would be a fine thing. My son – probably like your children - doesn't listen to me whatever I say.
We all know praise is essential both to develop a child's self-esteem and to counter the tellings off, which if you're anything like me, come much more naturally and frequently. Experts tell us we should remain calm and use a low, neutral voice when saying 'no'. If only those experts would issue instructions on issuing praise – 'keep it down' would do it.
It's not the praise that's at fault. It's delivering it on Spinal Tap's volume 11 amp that makes it ridiculous.
However tempting it is to blame noisy niceties on the emptiest of vessels, I think that's unfair – the vast majority of us admit we're clueless at this stuff. The difference is we'd really rather not draw attention to ourselves. (Unless we lose it and exhibit the other type of loud parenting – the fishwife yell of "YOU'RE IN SO MUCH TROUBLE".)
Parenting coach and mum-of-three Judy Reith explains how we should deal with it if we come across it.
"Parents are loud for three reasons. One, they have loud voices anyway. Two, they believe it's the way to get a child to pay attention, whether they're praising or telling off. Three, they want to be overheard, even if this is subconscious. Don't let loud parents interfere with how YOU want to communicate with your child. Praise their efforts, not results. Smiles, normal voices, eye contact and hugs go a lot further than a loud voice that a small child could find disingenuous and teens painfully embarrassing!"
You can follow Laura on Twitter @laurajanekemp