I have a new laptop on which everything compiles slowly. Which means I sometimes get really annoyed with C++ and its slow compile times. The two most common causes of slow compile times are large headers and complicated templates. Large headers are somewhat easy to identify, and you can usually improve your compile time by using precompiled headers, but it has traditionally been hard to find out which templates are hurting your compile time. Luckily there is a project called Templight which can tell you how much time Clang is spending on instantiating templates. Using Templight I have found that some templates take unnecessarily long to compile.
So I re-implemented std::unique_ptr, boost::flat_map, and await.