In Australia, they say the boil, rather than a boil, but most people we met say, a headache, rather than the headache, which you see in 19th century English novels. Then again, most people say the flu, not a flu, even though there are all kinds of flus (or is it flues).
If this sounds weird, consider whether you have the wrong number or you have a wrong number is correct.
For more fun, consider the Argentine, the Sudan or the United States and after a bit, you'll never be sure if you are using the right article in English or any other language.
