Curries didn't exist until the British decided to invent them. On arriving in India and sticking their flags in the ground, the British decided to investigate the local cuisine, and on discovering that the Indians had far more dishes and culinary skill than the entire United Kingdom, the British decided to hide this fact by calling every dish ever created by an Indian 'curry'. In this way, the Victorians could perpetrate the myth that the Indians weren't as cultured as they were because they only had one national meal, the curry, where the British had two, namely roast beef and fish 'n' chips.
A curry is generally accepted to be unspecified meat or prawns, smothered in a hot sauce and boiled in a large pot for days, possibly weeks. In this way the meat loses all its flavour and takes on the flavour of chillies, cardamon, garam masala, turmeric, coriander and bay leaves. If you visit the original home of the curry, your meal will often come with a side order of food poisoning to aid digestion.
The English tend to eat their curries hotter than anyone else. This is for one of two reasons: (a) it's one way to warm yourself up in what the English laughably call a temperate climate and (b) it is a test of manhood to be able to eat a chicken vindaloo without crying. This latter act has been celebrated in many parts of English culture, the most famous of which is the chorus of Duran Duran's 1982 hit 'Save a Prayer' ('Don't say a prayer for me now, save it 'til the morning after').