Microinterations are the glue that hold your app together. They are the details the devil likes to reside in. If you nail every microinteraction in your app combined with a good workflow you will probably have a great app. The definitive book on the subject is by Dan Saffer, "Microinteractions: Designing with Details".
Before we start to layout any wireframes or prototypes, the team works on the user's journey no matter how short that workflow might be. Microinteractions are a hot topic in UX Design currently for good reason - your apps are made up of dozens of smaller components that may have interactive components. So we work out the overall journey a user takes before working on features and the interaction of any components. After that, we can map our workflow.