I agree. I've spent the past 6-9 months cleaning up a .NET MVC project and one of the first things I did was to rip out all interfaces that weren't being used t

I agree. I've spent the past 6-9 months cleaning up a .NET MVC project and one of the first things I did was to rip out all interfaces that weren't being used the way I expect interfaces to be used. We have the base MVC project that references services for DI. We load in another DLL via Ninject to add customization on top of those services (custom parsing of some magnetic card swipes for different institutions we deploy to and such). I discovered that while all of our services (~20) had an interface, only one of them was being customized/overridden. This mean that in order to do something as simple as a parameter change, it had to be changed in way too many places: the definition, the implementation, and the usages. Why have that extra layer? If we need to override in the future, we can add more interfaces. For now, I just want to maintain my sanity.