Human faces are a big fascination of mine. I am studying the human skull again and again to better understand how and why we look different. Understanding the bone structure underneath allows me to create better character design once I start simplifying the face.
That's the secret to great character design. First, learn from the real world and understand the anatomy of the human skull and then start to simplify, not the other way around. Don't jump too quickly to conclusions that animators just draw cartoons because it's easier. You soon realise, creating a simplified face isn't as easy as it looks, if You want it to look believable.
But next to my character designs I just love drawing more realistic portraits with some fantastic elements.