Of course shadows can be good. As long as they are used well  – meaning not the “drop shadow on the side” you get when you use the pop-up flash on your camera. That one is a no-no.

But that does not mean direct flash is bad. Not at all.  Here, for example, the shadows really work to give an “in the spotlight” look:

Here, they add texture and liveliness to the subject:

Here, they add both spotlight shadows and strong patterns and leading lines:

Here, the shadows add to the otherworldly quality:

Your next assignment, should you choose to accept it: use shadows creatively in a photo.