> That one does leak a bit in some places: for example, pressing the pedal isn't linear. That’s the least of your problems, because it leaks profusely. We coul

> That one does leak a bit in some places: for example, pressing the pedal isn't linear. That’s the least of your problems, because it leaks profusely. We could start with the fact that in many scenarios the “accelerator” pedal does not, in fact, accelerate. This is not an edge case—any driver who had to drive on ice, snow, dirt or otherwise not have traction knows that. What it does do reliably is make the wheels (some or all, depending on your car) go faster. > But ultimately that doesn't really matter; the person driving gets used to it in very short order. Let’s recap. I believe you were saying that the abstraction is leaky, the system does not always do what we expect, and even though many of us don’t really care to understand how the system works it’s OK because we sort of adjust and roll with it because for all its faults the system is good enough (and, perhaps much more importantly, we’re used to it). Hold on, it’s almost as if you’re talking about one well-known version control system… …and on balance I’d agree with you, except I think a serious software engineer is more like an auto mechanic or professional racer rather than a casual driver—“press the pedal to go faster” doesn’t really cut it, and we should have a good and correct model of how Git works.