When writing a container, I'd actually prefer to open namespace std and overload std::begin and std::end for my_namespace::container. That way, I'd be free to use my_namespace::begin for something else, which IMHO is the point of namespaces. But having ADL and being able to re-open other people's namespaces is definitely unfortunate.

I love the Objective-C convention of just using three-letter prefixes for everything. I'll miss its pragmatic approach.