BEFORE I left on my Sri Lankan holiday, I made sure I got shots for typhoid and hepatitis, got pills for malaria and gastro, and got a mosquito repellent for dengue fever - a heavy-duty 80 per cent DEET one with the instructions ''May dissolve plastics, rayon, and vinyl car seats. Apply evenly to skin''.

But for some reason I completely forgot to take any health precautions for Earnest Try-Hard Patronising Western-Tourist Disease and, oh man, I came down with a shocking case of it. It's a travel ailment that middle-class Westerners can get in poor or developing countries, particularly if they have direct contact with locals, visit public places, or eat any food during their stay.

Sri Lanka is a magnificent little island just south of India, and the moment I arrived, serious symptoms kicked in. Lower-jaw soreness from constant smiling at every local I passed, one lip-corner twisted up in a perky, exuberant way, the other lip-corner bent down in a humble, non-threatening way, so I looked scary, like Heath Ledger's Joker. And I began suffering mild back pain from insisting on carrying my own luggage in hotels: if a porter tried to help, I'd give a polite nod as if to say ''I am not your white colonial master, you do not work for me, we are equals, OK?'' And they'd give me a polite nod back, as if to say ''You are aware I live off tips, right? Guess my family won't be eating this week. Still, thanks for your condescending white guilt, means a lot.''

Over the next few days I developed stiff, aching leg joints from walking around everywhere ''to immerse myself in the local atmosphere'', accompanied by painful, bleeding fingers from excessive Lonely Planet page-flicking (the 1980 edition with the heavier, slashier paper stock). Also, a stooped buckled spine from bending down to hand money to every beggar on the street, one of which turned out to be a miserable German tourist resting on a kerb. And a burning, churning gut from eating at street-vendor stalls, enjoying fetid curries from rusty buckets because I thought that's what the locals ate, but turns out the locals were across the road in the fancy, clean curry place with the mood lighting.

Thankfully I'd brought along a pack of Gastro-Stop, but why hadn't I thought of bringing a pack of Gumpo-Stop to control my unstoppably irritating obsequiousness?

On my last day I was slumped over exhausted in a hotel foyer, my eyes bloodshot from excessively friendly eye contact, my neck paralysed from over-peachy nodding, my throat raw from speaking to everyone in an embarrassingly pointless pidgin English, yelling it so they'd understand better. I spotted a painting of a forest on the wall so I turned to a passing houseboy and said ''Beautiful picture, yes? YOU UN-DER-STAND? BEAUT-I-FUL'' and he said ''Yes sir … it is … Sri Lankan forest … and it is filled with - with - ''

Poor fellow, he couldn't think of the English word, so I tried helping him; I said, ''Filled with trees, yes? YES?'' He said, ''No, not trees …'' I said, ''Animals? YES?'' and he said, ''No … uhhhh … no …'' But he couldn't think of the word so he went off to ask the hotel receptionist and they discussed it for a while, then they both went off to ask the hotel manager and they discussed it for a while, then 10 minutes later the houseboy came back to me all excited. He said, ''Biodiversity''. I just sat there blank-faced. He leaned in closer and yelled, ''Bio-di-ver-sit-y, yes? YOU UNDERSTAND, YES?''

Columnist Danny Katz's latest book, S.C.U.M. (Allen & Unwin), is out now.