It's hard to see why cars are a passion for many, because to the mass majority of the people, cars are just a means of transport - something more comfortable than walking, and a faster way of travelling from A to B.
Then there's the driving bit which gets worse, if you live in the city it'll make you go mad every time there's a traffic jam because you'd go mad getting stuck behind cars, and it does happen rather often. If you need to go from one place to another rather far away rather brisk, you'd probably choose a plane or a train to save the hassle of actually driving the damn thing.
But why? Why do people like cars? They aren't particularly efficient, they aren't the fastest things on Earth, they don't sound that impressive on paper.
When cars were first invented, people, of course, didn't know what they want. Because when Henry Ford asked what products do they want, they'd simply say 'we want faster horses'. So Henry Ford neglected them and built cars, which are just 'faster horses', except cars aren't really horses.
As time goes on, cars turn from a necessity to a bit of a hobby. Again, it's like horses, horses were a necessity back in the days, but people turned them into a hobby, horse racing, vaulting etc.. It's the same theory with cars. That's why we use cars to do all sorts of stuff. We race to see who built the best cars, we race to see who is the best driver, we modify to see who's the most artistic. Cars are a hobby.
Furthermore, we get emotionally attached to cars. Cue Richard Hammond, who has fallen deeply in love with his Opel Kadett that he bought on the Top Gear Botswana Special. The Opel is not a special car by any means, but after a few miles, they've been experienced rough terrains, breakdowns and spent endless hours stuck together. So they've bonded, they're mates, much like brothers. The Opel even has a name - Oliver, which shows you just how attached a petrolhead can be with a car.
Cars are also an extension of personality, what you drive says a lot about you. People who drive Volkswagens would tell people that you're very sensible and a bit boring; driving Alfa Romeos, on the other hand, would mean that you yourself are Italian, brash, pretty and often very positive because they would break down all the time, you have to be.
The brands themselves is only one way of telling people what sort of person are you, modifying a car is another story. If you build a sleeper car, with oodles of horses under the bonnet and not much on the surface, that would make you a not-so-shouty person but very talented; if you have a show car, it means you're very artistic, you pay careful attention to every nut and bolt.
Cars also give you a sense of freedom. Often if you're depressed at night and you want to escape the world, you'd hop into the car, start the engine, and stomp on the throttle as hard as you can. Everything feels under control, you have the final decision of where to go, and how fast you want to go there. The go-anywhere nature makes it stand out from any other means of transport, you can't just go-anywhere in a plane, or a train, or a bus right? But you can in a car, and that's what excels.
Cars, to we petrolheads, aren't just a way to go from A to B. It's our passion, it's the emotional bond that you just don't get from any other ways of going places that makes us petrolheads. It's what cars say about us and the personalities of the cars themselves that makes the term 'car' so attractive. They aren't just cars, they're our mates, and what a passion this is.