After taking him through some basic training - he commented to me that he didn't expect making coffee to be such an "intellectual pursuit." I asked him what he meant and he replied (and I'm paraphrasing from flawed memory) something like:
I thought that making espresso would be more like an art - with a lot of self-expression going on. But it's not really like that. It's also not like science - because it's really about producing something that tastes good (an inherently subjective goal). It requires right brain and left brain thinking.
He's an engineer by training - who ended up working in marketing for Apple. It should have been no shock that he was producing decent espresso quite quickly given this and his comment above.
So... the Art v Science argument (schism?) has been a long-standing situation in coffee (pro and amateur). But after talking to my friend, I realized that both are false choices. The reality is that it's neither.
Making great coffee is a craft in the truest sense of the word. Keeping this in mind is likely to be a simple trick for determining what really is important and what is not.