I see you are having a very serious discussion about human evolution.

At the end of the aisle, the problem becomes apparent: since the last time I visited Sainsbury's, four central checkout bays have been replaced by eight self-checkout points. The majority of the people using these are doing so only because they have joined the wrong queue, and most are now behaving as if they are scanning their purchases in a low-oxygen environment. It's not their fault - self-checkout is useless, and there's only ever one member of staff to help, and he's always busy helping someone else who has somehow managed to charge himself 80 quid for his own sleeve - but their frustration provides something to watch when you're still too far away to reach the magazines.

Over the course of the next quarter of an hour, I gain four trolley lengths on the self-checkout queue to my right, where a woman has been attempting to weigh the same aubergine for the better part of the afternoon. Her plight is drawing pity and resentment in equal measure.

"She'll never use that thing again," someone says. No, I think, and neither will any of the people behind her.

I manage to get my items on the conveyor belt, but the woman in front of me, having completed her purchases, is now with great deliberation selecting items from her shopping to be unpurchased. I make the mistake of wondering if and how things could get worse.

"Who wants to buy a red nose?" someone shouts. I look up. A man and woman dressed in red uniforms are striding past with a bucket of red noses, grinning broadly. The man has a video camera. They are the only people in the building who are currently in a red nose kind of mood.

"We need someone to buy a red nose for the camera!" shouts the man. They stop directly in front of me. I am giving a pet insurance leaflet my fullest attention. I can feel the camera on me, waiting for me to look toward it. "Just one person to buy a red nose!" he shrieks. "Sir! Would you like to buy a red nose? Sir!" I am never coming here again, I think.

Two days later I am there again, in the same queue, facing the same chaos, trying to will the man currently bagging his groceries to behave less like he is preparing antiquities for overseas shipment and more like he is evacuating a flaming plane. Next to me a woman with three children is desperately trying to scan a six-pack of tinned tomatoes, only to be told, over and over, that there is an unexpected item in the bagging area.

"Bleach!" she suddenly shouts, pointing at her small son. "Go down that aisle and get some bleach. Lots of bleach. It doesn't matter what flavour." She means to drink it, I think. I hope the kid brings back enough for all of us.

continuously complain about unknown items in the baggage area without ever raising its voice or sounding frustrated. At least if the system felt as frustrated as myself when I used it, I'd feel better!

Evolution is not behaving like a machine!!!

and so that i'm not accused of trivializing a serious discussion about evolution,

Interbane wrote: We have evolved the tendency for false belief. Since there is no filter in our brain about what is true and what is false, we must excessively believe; it is safer to believe in danger than to not believe, therefore such belief is of survival value. Our traits have served us well and we're now kings of the planet, but we need to wage war against the beneficial-turned-detrimental trait of excessive belief.