Well actually, around two and a half years ago, I decided to start a fansub for my country's language.
I was part of a Portuguese anime forum and I suddenly felt the urge to sub something, I picked some friends from the forum and the fansub was created.
However, all of us were n00bs and didn't have any experience in the matter whatsoever. I, for instance, could only do QC, and my friend co-founder could only time.
After struggling with staff members and hate from other fansubs, I knew that only being able to QC was not good.
Since most of the staff members (putting aside good translators) just "ran away", I decided to learn other jobs more important in the fansub.
For instance, I started by learning how to time, which I really enjoy if I like the anime, and since by being the boss I can choose most of the shows I do, it's pretty difficult to have to time a show I don't like.
Then due to university, my co-founder didn't have enough time to execute fansub tasks in a regular basis, and decided to do only the design for the site/forum, and I had to find other people for the staff or learn the job.
So I poked lots of encoders until I learned to do good encodes, I also learned how to typeset, edit, style, etc...
The only things I can't actually do now are Translating and K-Timing/Styling, the first one for obvious reasons, and the second one because trying to do it just pisses the hell outa me.
So basically, I learned all these fansub jobs out of need.