What is an example in which knowing C will make me write better code in any other language?

Question

In the Stack Overflow podcasts, Joel Spolsky constantly harps on Jeff Atwood about Jeff not knowing how to write code in C. His statement is that \"knowing C helps you write bet

Answer 1

In Python, say you have a function

def foo(l=[])
  l.append("bar")
  return l;

On some version of Python, available about a year ago, running foo() for times, you'd get a really interesting result (i.e. ["bar","bar","bar","bar]).

It seems that someone implemented the default parameters as a static variable (and without resetting it), so unexpected results happen.

Perhaps my example was contrived - a friend of mine who actually likes Python found this peculiar bug, but the fact of the matter is all of these languages are implemented in C or C++. Not knowing and not understanding concepts that are fundamental to the base language means that you won't have an in-depth understanding of languages that are built on top of that.

I find all the "why bother with C/C++/ASM question silly". If you're inclined enough to learn a language, that means that you're curious enough to get into it the first place. Why stop at just before C?