I was given a Vic-20 by my parents for Christmas one year when I was about 10 instead of the Atari 2600 I really wanted. I did enjoy the game that came with it (Radar Rat Race) but was still disappointed. Later that day I cracked open the manual and began typing in the commands. "HELLO, WORLD!" appeared on my screen. Eh. And then an animated ASCII jumping-jack man. That's pretty cool. And then a program that asks for your age, runs it against several IF-THEN statements and prints out an answer based on your age.
What a second. What?
So I added numbers together and did more IF-THEN checks. Holy fucking shit. I realized at that moment that I could do anything with these commands. I could create any program I wanted including games like Pacman. There was no limit. I had the Power.
So I programmed hardcore for the next 6 years. I became very good in Basic and proficient in machine language. And then I stopped programming around 17. I was burned out and it wasn't fun anymore.
Eventually I became a music major (composition) and gave up on computers altogether. Then a few years ago I came up with an idea for a super massively large music generating program. While I had forgotten how to program and had no feel for modern technology (when programming) and anything that had happened in languages in those 30 years, I still knew how to think like a programmer.
I chose Lua for this project (which didn't even exist when last I had typed code into a machine) and have become fairly proficient in it (some 6000 lines of code or so).
So yeah, entirely self-taught and then re-self-taught.
I have some huge gaps in my knowledge concerning really cool mathematical algorithms that I'll probably never learn. But I'm not really a programmer. I'm a composer using programming to realize a bigger project.