A bit off topic, but you triggered something I've been thinking about for a couple of years. That "spark" is fluency.
I swtiched jobs from being a computer programmer to being an ESL teacher in Japan. Japan is somewhat famous for churning out students who know a lot *about* English, but can't order a drink at Mac Donald's. We used to have a name for those kinds of people with regard to programming languages: language laywers. They can answer any question you put to them *about* a programming language, but couldn't program to save their life. These people often make it past job interviews easily, but then turn out to be huge disappointments when they actually get down to work. I've read a lot about this problem, but the more I look at it, the more I realise that these disabled programmers are just like my students. They have a vocabulary of 5000 words, know every grammar rule in the book but just can't speak.
My current theory is that programming is quite literally writing. The vast majority of programming is not conceptually difficult (contrary to what a lot of people would have you believe). We only make it difficult because we suck at writing. The vast majority of programmers aren't fluent, and don't even have a desire to be fluent. They don't read other people's code. They don't recognise or use idioms. They don't think *in the programming language*. Most code sucks because we have the fluency equivalent of 3 year olds trying to write a novel. And so our programs are needlessly complex.
Those programmers with a "spark" are programmers who have an innate talent for the language. Or they are people who have read and read and read code. Or both. We teach programming wrong. We teach it the way Japanese teachers have been teaching English. We teach about programming and expect that students will spontaneously learn to write from this collection of facts.
In language acquisition there is a hypothesis called the "Input Hypothesis". It states that *all* language acquisition comes from "comprehensible input". That is, if you hear or read language that you can understand based on what you already know and from context, you will acquire it. Explanation does not help you acquire language. I believe the same is true of programming. We should be immersing students in good code. We should be burying them in idiom after idiom after idiom, allowing them to acquire the ability to program without explanation.
Wonderful comparison between learning natural languages and learning programming languages.