1) all abstractions leak. We use them anyway because they are helpful, but you have to be expert enough to know when they're leaking, and know what to do about

1) all abstractions leak. We use them anyway because they are helpful, but you have to be expert enough to know when they're leaking, and know what to do about it. This invariably requires understanding the system underneath the abstraction. 2) I disagree that there is "no intrinsic value" in this knowledge. Even in purely monetary terms, my salary is much higher because I like to look underneath the abstraction. I agree that in our modern software systems that it is not practical to understand everything, and it's usually most "cost efficient" to operate at/near the highest abstraction layer. But this does not bring me joy! and what "intrinsic value" is there besides happiness?