Finding weird corner cases may indeed be very hacker-ish, but blindly labeling them as good is not, in my opinion. Did Thomas do that? I don't see anywhere whe

Finding weird corner cases may indeed be very hacker-ish, but blindly labeling them as good is not, in my opinion. Did Thomas do that? I don't see anywhere where he "blindly label(s) them as good". Right there in the title he calls them Quirks, and he says you have to love them. Then, in the text he explains, quite clearly, that you should almost never use these in actual code. I think you've missed the point that the examples presented (especially the function definition in a default argument) merely show how Ruby works; specifically that all code is executed as expressions during runtime. To me these "quirks" are similar to showing somebody that dereferencing an offset to an array pointer in C is the same as using an array index. You're not going to do it in production code, but knowing that it's possible helps in better understanding what's going on with all that code you write.