What's C's biggest mistake?

[Walter Bright]

Don wrote:
> Well, if you ask the question "what's C++'s biggest mistake?" it's much 
> more difficult. C++'s failure to specify the ABI is enough of a reason 
> to use C instead, I reckon. It think it's an appalling, inexcusable 
> mistake -- it guaranteed compiled libraries 20 years later would use 
> extern(C), not extern(C++). And that's not the worst C++ mistake.

I'd be hard pressed to come up with C++'s biggest mistake. Perhaps it 
was failing to address the array => pointer conversion.