"smart" and "gets things done" are sufficiently vague that they can mean whatever you want. If I say "So-and-so is smart, however X," the reply can always be "Well, if X then so-and-so isn't truly smart" in the No True Scotsman sense.
This is why I tried (perhaps poorly) to be specific and talk about smart in the sense of mathematics.
I think in the instance you described you were and weren't being smart in the sense of a True Smart Scotsman.
Mathematic smarts isn't always enough to know how something really works. But I still think you were smart enough to realize you might be wrong and to double check how it really works.
Also, you have the GTD mindset to accept how Proc works and try to learn from the experience instead of obsessing about how Proc is broken and ruby sucks.
This is why I tried (perhaps poorly) to be specific and talk about smart in the sense of mathematics.