Working in the Bus industry you learn a lot about the obsessive nature of men. I once had an hour long conversation with my first manager, who like me had come in from outside the industry, about that very subject. She had a great deal of, understandable, disdain for what she referred to as "Bus Nuts" and I tried to explain to her that most men had obsessions. With most it's sport, usually football, or music and because of the prevalence these are considered acceptable, if often boring or annoying if to extreme. Then there are the others, those who hold a relatively obscure obsession. For some it's Hornby model trains, or the Napoleonic War, or comics, or skateboarding or James Bond or Star Wars or one of a million other things that are harmless and come with some sort of less than flattering stereotype. Happily most, on closer inspection, include a broader scope of people and put a lie to the stereotype, but not, so far as I can see, the bus nut.
One of my colleagues, who works in the engineering department and has to deal with a lot of enquiries about the fleet from "enthusiasts", has described their mania as bordering on autism.
For pictorial interest only, This is a bus
From Wikipedia (admittedly not the best source but the easiest to access and understand) comes this definition "Autism is a brain development disorder that impairs social interaction and communication, and causes restricted and repetitive behavior". Add to that an obsession with numbers, lists and order and you have a fair description of the average bus enthusiast. It's almost scary how some enthusiasts can give you an entire history for a particular vehicle based solely on it's fleet number. They'll tell you where it's been in service, what make of vehicle it is and it's age, what livery it's painted in and a whole host of other facts that sail far over my head. But even then there's a split between those who have personal hygiene problems and live with their mothers still and those who can pass as normal. Last week two of my colleagues, who seem like normal people most of the time, had a twenty minute conversation, with impersonations, about the noise various types of bus made when you first turned the engines over. It's one thing to hear fat, sweaty men with coke bottle glasses, body odour and an inability to dress themselves have a conversation like that and quite another when it's two people you like and respect.
My comics obsession has never really plumbed that sort of depth but easily could. Though I no longer follow superhero comics and rarely read them now except in the occasional collection borrowed from the library, it's all still there, bubbling under the surface. It wouldn't take much to get me going on "who's the best Green Lantern" or "who's strongest, The Hulk or The Thing". I guess when you're as closed to being branded with a stereotype as I am it makes you a little more aware about writing someone off as a "nut".