I can't remember what made the penny drop. It may have been the clip-clopping of high heels against tiles. Or the unnaturally sweet smell in the air. Or the bin next to the lavatory. But I recall all too well the moment I realised that I'd inadvertently run into the Ladies.

There were several layers to the horror: the blind panic of wondering how to escape without being spotted or arrested; low-level resentment at how much cleaner women's loos are than the Gents; dismay at the number of “ladies” who could be heard entering and leaving without washing their hands.

And on escaping without being spotted, flitting out faster than Dwayne Chambers during his drugs period, I dealt with the mortification by pretending it hadn't happened. But it all came back last week when a visit to the bar in question made me realise that it hadn't been my fault. And it hadn't been my fault because it turns out the loo doors weren't marked with conventional “Men” and “Women” signs, but with entirely indecipherable brass plaques, featuring faint, seemingly androgynous, figures.

A Google search reveals that it's a trend: traditional toilet signs everywhere are being replaced by word pairings such as, “señor” and “señora”, “blokes” and “sheilas”, “buoys” and “gulls”, “wahine” and “kane” and picture pairings such as Roger Rabbit and Jessica Rabbit, Homer Simpson and Marge Simpson, Marlon Brando and Liz Taylor.

There's even a blog that collates examples from around the world called “The Toilet Signs project”, which claims that its photographs of loo doors “show us that art can be anywhere”.

But I disagree. What all these signs actually reveal are two worrying trends: 1. corporate infantilism, where businesses are increasingly attempting to establish emotional connection via cuteness; and 2. overdesign.

I've been trying to articulate why the latter is more concerning than the former, but every time I try - arguing, for example, that prettiness and wit are pointless in design if they result in products being divorced from function - I sound like Jonathan Meades on a bad day. So to put it more simply: design is irritating when it gets too poncy. Which is not to say good design isn't something to aspire to. My desire for the new iPhone is almost physically painful to endure. And I'll even concede that some of the aforementioned toilet signs - in particular “buoys” and “gulls”, from a seaside seafood restaurant apparently - are fun and witty. Moreover, there is such a thing as too much functionality. The Highway Code's warning sign for elderly people, showing a decrepit couple leaning on each other, has always struck me as depressingly vivid, just one step away from a silhouette showing them being beaten up in a care home. And some of the toilet signs featured in the aforementioned blog, showing figures in various states of lavatorial undress, provide way too much information.

But great design is only great if it is both pretty and functional. And toilet signs that require a PhD in semiotics to comprehend really don't work. There are other offenders: corporate logos rendered illegible by overdesign (check out: www.zumosmoothiebar.co.uk); websites so fancy that they are impossible to use (www.pageonebookshop.com); hotel rooms filled with banana-shaped chairs you can't sit on and fitted with showers with so many knobs and levers that it's like operating a steam engine.

Though you'll have this problem only if you actually manage to find your room: another symptom of design ponciness is that hotel rooms are increasingly being given names rather than numbers. The same is happening with houses. A third of every car journey seems to be taken up with driving up and down a suburban street, squinting at front doors, trying to find “The Willows”.

Which brings us to car manufacturers. It has become obligatory for vehicles to feature a sporty “Start” button on the dashboard, but very rarely do they actually start when you press it: you usually have to press a combination of pedals, turn an ignition key, have the car in a certain gear and pointing towards Mecca before it works. The only vehicle I've driven where this is not the case is the fabulous new Jaguar XF - in-built gadgetry senses you have the key on your person, you press Start and it goes.

Indeed, companies such as Jaguar, Aston Martin and Apple appreciate the importance of functionality. Conversely, the patron saint of overdesign is Philippe Starck, whose most famous artefact, the legendary Juicy Salif cast-aluminium lemon squeezer, looks like a three-legged spider and is about as effective as an actual three-legged spider at squeezing fruit. The Frenchman has himself admitted: “This is not a very good lemon squeezer.” He continued: “I thought it would make a nice wedding present for couples.”

The argument is ludicrous: like designing a house that falls down, but saying it's OK because local kids enjoying playing with the rubble. And it's time such silliness came to an end. I was going to say that what we need is a design equivalent of the Plain English Campaign, but maybe it would be better to have a wider-ranging version of the programme the Chinese now have in place in Beijing: in preparation for the Olympics the city has embarked on systematically rectifying misleading English signs around the city - changing “export” to “exit”, and so on.

We could have a similar crackdown on crap design in the run-up to the London 2012 Olympics and after rectifying all those misleading toilet signs, we can get working on our illegible Olympic logo.

sathnam@thetimes.co.uk

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