Interesting question... For me it started with music. Music was in my family. My grandfather was a orchestra conductor. I played in high school band and sung in high school chorus. I always loved to listen to music and later loved movies. I also have a "quality" bug built into me somehow* so I've never been happy with poor quality sound or video reproduction and was never tempted by garbage stuff I saw people buy because it sounded and looked so bad.
When I was in high school I didn't have anywhere near the money to afford my tastes in sound, but a local dealer talked me into buying good quality used components over junky new "stereos" for the same money. It wasn't great, but was still sounded better than that of my friends and in my college dorm.
The first defining event for me was one evening as a college freshman when a bunch of us gathered to listen to classical guitar played through a nice stereo in the dorm mother's apartment. I was completely taken away by the realism of the guitar and never forgot that experience. The nuiances of live quitar recordings are still a reference to evaluate audio equipment for me.
The next event was years later when I was invited to "movie night" at a friends house. She and I both had Beta HiFi VCRs and it was basically at the end of the Beta era and I felt I was being forced into VHS for lack of media. She and her boyfriend just bought a nice Pioneer LaserDisc player. I don't remember what we watched, but it was in letterbox and I knew I had to have one. I already had something of a HT setup with a Pioneer Dolby Surround receiver to go with the Beta HiFi tapes and a 27" flat tube "big screen" TV, so LaserDisc and letterbox was a perfect match. I think I got my LaserDisc player less than a week later! It felt like real HT then.
People just couldn't believe the difference between that and VHS. I used to demo a couple of movies to people switching back and forth and it just amazed people to see the detail they were missing on tape. And I beg to differ with the person who didn't think LaserDisc was better than tape. I can easily show the difference in both picture and sound! (Though I admit that last of good tapes were a lot better than the ones I had seen in the early days).
One day I happened upon a used $10,000 JVC 55" 16:9 TV for sale in the local want ads for "only" $2000 and knew it would be perfect for my letterboxed LaserDiscs. (This is a NTSC set, not an HD. HD at the time was about $20,000 for a set my size, $15,000 for a smaller one). And it was great for the LaserDiscs! So now I had a Dolby ProLogic receiver, a theater size TV, and widescreen movies on LaserDisc. Life was good!
When DVDs came out I was skeptical (LaserDisc fans all "knew" there'd be too much compression to get all the video information on a tiny little disc and DVDs would be basically VHS quality on disc). But then I heard some good things about DVDs and also that they were in anamorphic widescreen. My TV had a setting for that which would mean I could finally see widescreen movies in the full resolution of the TV! So I rented an early DVD player and I was completely blown away by the images! Literally sat with my mouth open!! I had no idea my TV was that good! I bought my first DVD player less than a week later! Next a Dolby Digital (ready, since the player had the decoder built into it) receiver to get the discrete 5.1 sound.
But it all goes back to the early events where I heard great sound, I had seen movies in theaters and wasn't happy with the typical movie on TV quality and wanted better.
Being "just a girl" I am not often taken seriously at stores, or seen as weird by others because I know about, and have decent equipment. But unlike some people for me it isn't about the equipment, it is all about the experience. I've had to learn about and appreciate the equipment to attain the home experience in music and movies I want.
Thanks for listening,
Marie
* P.S. this is consistent everywhere in my life. I want a quality AV experience, as much as I want quality furniture, kitchen workings, cars, shoes, and clothes. Some in this forum may be amazed to learn that I've spent more on on one Escada outfit than I have on my most expensive piece of HT equipment.