Creating prototypes are a great way to test your designs and communicate to developers what we are building. But for me, the act of building it allows me to think through all the intricate details at more depth than if I were just creating static mocks. It allows me to think about error cases and paths beyond the happy path. It lets me think deeper about how I can use transitions and animations to help the users retain context. This is demo reel of several prototypes I have built. Yeah, I spend a lot of time prototyping.
BTW- My tool of choice is Axure RP.