I learned that many programmers are musicians or good at various art forms. Which surprised me because I was a good programmer and can't play a musical instrument or do anything artistic at all.
Music is basically counting and patterns, something that should come naturally to most programmers. The music theory jargon can easily go over your head at the beginning but you don't need to dive into it to actually play music at a basic level, and after you get some practise and a feel for it, the more advanced stuff start to make sense.
The hard part is actually getting some level of technical proficiency over your instrument of choice, dexterity is rarely useful in real life but it's the basis of playing most instruments.
If you can whistle a tune you can play music, getting control over the new medium (the instrument in this case) is the biggest issue, as the learning curve is highly steep and the fact that you'll initially sound like crap doesn't provide adequate positive re-enforcement, something necessary to any learning process.
Also, the fact that the cheap learner instruments sound really bad and are much harder to play than the expensive awesome sounding stuff doesn't help either.
PS: I'm an amateur self-taught guitar player, maybe someone with actual training can provide a better perspective.