For example, I just recently started using Boost. Holy smokes, it is BEAUTIFUL, at least the parts that I've used. It just works. I've never worked with a library where I look at the example, make a guess as to how it should work, and it just works. On the other hand, the company I work at uses Boost in a completely illegible, unmaintainable way. It has nothing to do with Boost, it's whoever uses it.
To say a language such as C++ is responsible for overly complicated interfaces is just plain dumb. It's not the language it's the implementer. I can take the same $200,000 violin as Joshua Bell and make horrendous sounds from it. It doesn't mean that the violin is a piece of crap, it just means that I have no idea how to play a violin.