The importance of anatomy.
Understanding anatomy is crucial to many aspects of your art.
You'll notice that anatomy is essential for drawing. It becomes difficult to accurately draw a complex pose, or even a simple one, if you don't understand what's under all that skin or fur, or even bark. Knowing how everything fits together is important.
Once you notice where that certain muscle is, shading and form become much more accurate and more natural. Knowing why the nose and eyes fall where they do make it much easier to draw from memory, and nail that natural look you were going for.
Learning the anatomy of the subject you're going to draw