The biggest quest in fashion is not the ability to look good while dressed up, because it's not that hard: just a question of throwing enough money in the right direction. No, the Holy Grail is looking good when dressed casually. And, within the spectrum of dressing casually, at the very far end (ergo, the very hardest things to look good in) are working-out clothes.
I envy girls who look good in the gym. Not, by the way, those in ridiculous candy-coloured Juicy Couture velour tracksuits, the very uniform of chavness. Not even Madonna looks good in one; and anyway, velour tracksuit bottoms have a very unfortunate side-effect in that they give women what's called the "camel's hoof effect" in the reproductive area.
Some years ago I interviewed the designer Ben de Lisi, and he told me how he'd met his muse and business partner, Debbie Lovejoy (I mean, what a name!). When she first dropped off her CV to him, she told me she'd been "looking pretty dreadful, wearing an old pair of trackpants". De Lisi's version was slightly different: "Yes, but they were Joseph tracksuit bottoms," he said, a bit wistfully it seemed to me. This, I thought, was class.
Since then, I've made it my mission to look good in trackpants, but have failed at every hurdle. For one, I get to the till and cannot part with £50 upwards for trousers I will sweat in, so instead go to Marks & Spencer, pay £15 and am left suitably covered, but perennially disappointed at the lack of designer glow they give me.
Then there are the tops. The good (designer) ones are all spaghetti straps and often have flowers on the chest-area, which are really no good for girls like me who need to wear at least two bras when working out (one of which is the excellent DanSport Minimal Bounce Bra, which really does do what it says on the label), and the said little flower ends up stretched into Triffid proportions.
So I end up in a black T-shirt that does no one any favours, although it sets off the purple in my face - the colour I am after a trip to the gym - rather nicely.
When I go to yoga, it's all girls in apricot and lavender-coloured Nuala, the sports label designed by the model Christy Turlington for Puma, empire tops and slouchy boxer-pants. Or they're dressed in little T-shirts and bitter-chocolate or bubble-gum pink Calmia "practise pants" - with the roll-down waist permanently, and very expertly, rolled down.
After stretching into the downward dog and flipping their dia phragms in the fish pose, they slip their feet into soft-lea ther, slipper-type shoes (Prada, Tod's) that tell me their soles travel rarely across pavements or down Tube escalators.
Then they put on warm-down fleeces that would make me look like a red-neck lesbian, but they manage to look all delicate and glowing in them, in that annoyingly, nonchalantly beautiful but casual way.
It's hard not to hate, even when your heart is meant to be all full of peace, and you've been ohming extensively.