#defining {

When I first conjured the idea of MCI, I thought about making it look completely transparent. I wanted to #define the opening curly brace like this: 
#define {  { Mci m(...);

The code would have looked totally normal (sans Mci), but under the covers, MCI would have done its stuff. There are many problems with this approach, such as the fact that every opening curly brace gets an MCI object including regular scope braces (if, while, for, and so on), and braces in namespace, enum, struct, and class definitions:

namespace { Mci m(...);
enum { Mci m(...); SUNDAY, MONDAY... }

Yet, what really threw me off this track is the simple fact that you can't #define curly braces. If I think objectively about it, it looks like the only advantage for this approach is the "Wows" I would have gotten from my colleagues (which clearly makes it a worthwhile endeavor).