Most photographers don’t know anything about how to use a flash. They’ll generally put it on their camera, aim it upwards towards the ceiling (or directly at their subject) shoot, and worry about it later. Nothing could be more incorrect about that unless you’re specifically going for that look. The problem is that most people aren’t going for that look. So instead, they sit there frustrated about working with a flash.
First off, start by considering that a flash isn’t just for adding fill light to a scene. Instead, think about it as a way to creatively elicit a feeling in a photo.