I use WPF everyday and it has many great features. But sadly it was conceptualized before many of the 'modern' and best features of .net. The striking lack of type support (generics), and frankly broken separation between form and function, makes it feel very clunky at times. Not to mention that while data-binding is first class, the predominant MVVM pattern is sadly bolted on. My last gripe is that in most WPF applications, the only reason the application hangs is due to rendering performance - which is truly unacceptable given every other part of my application can be multi-threaded or async.