You have only to sit in a cafe frequented by expats to come to the inescapable conclusion: Westerners are frumps. It is bad enough that we are red-faced hairy giants, with noses that give children nightmares. What makes it worse is that we do not have a clue how to dress properly.

Back home the Westerner goes about sensibly clothed in trousers or a skirt, usually in muted shades. But as soon as a hot sun beats down upon his or her skull, a tiny chemical change is triggered in the brain. Perhaps it is genetic, handed down from an era when our ancestors roamed the tropical savannah. Or perhaps it is the result of watching too many travel programmes on TV. At any rate, a subconscious command is passed to the motor cortex of the Westerner’s brain. It is simple. It says: Wear shorts.

Shorts are, without a doubt, the most ridiculous garment ever invented in the history of costume. If you thought the bustle, the corset or spats won the prize, you were wrong. (Sandals worn with socks come a close second.) Shorts are just about acceptable on small boys or the pouting sirens who recline on car bonnets at motor shows. On the rest of the human race they look preposterous and no more so than on people who are tall, fat or over 40. Which includes most Westerners in Indonesia. Their other disadvantage is they make you look like a Dutch colonial planter.

Undeterred, the great-arsed foreigner squeezes into them and marches about the town, to the delight of the residents.

The other ubiquitous item of clothing favoured by Westerners is, of course, the T-shirt. This garment does not look good when stretched over a large surface area, especially one that owes its shape to a beer gut. Generally, clothes are supposed to disguise, not accentuate, the less attractive features of the human form.

On holiday it may seem natural to disport yourself in a Hawaiian shirt and silly sunhat. Looking like a clown reminds you that you are meant to be enjoying yourself – in only two weeks you will be back in the morning rush hour in a less agreeable climate. When this spirit lasts for 52 weeks a year, perhaps you should do a reality check. Am I still on holiday?

This is a particular problem for the hippies, surfers and dropouts who, after months of lounging around in Indonesia, discover their money and visa have run out. They resign themselves to doing some work and, as they cannot face anything complicated or strenuous, they decide to become English teachers. They present themselves at language schools in frayed cut-off shorts, sandals made from car tyres and torn, grubby T-shirts. If male, they will not have shaved for several days. The school director will not be listening to their incoherent theories about teaching. He will be wondering whether to have his office fumigated.

Some Westerners try Indonesian traditional clothes. The men don a pici or a batik shirt of the sort that is worn at office functions and weddings. The result is rarely flattering. The women confuse colourful wall hangings with articles of clothing. Wrapping them around themselves with the idea of looking like a Javanese princess, they resemble nothing so much as gaudy sacks of potatoes, tied up at the top.

But perhaps this is all in the nature of expat life. Do Indonesian residents of the colder Western nations wear ski suits, woolly hats and furry gloves all the time, while the more flamboyant dress up in kilts, clogs and lederhosen? It is a possibility.