Some panels and tools just don't get the love they so rightfully deserve. The Appearance Panel is like that third Olsen Twin sister, the one that's not a twin. Wait, Elizabeth Olsen is more famous now?? Anyway, the Appearance Panel is packed to the brim with useful features you should be using in your day to day work flow. I'm not talking about editing a drop shadow. I'm talking about knowing how to use it properly to editable type in order to make future changes and experimentation as easy as it can be.
So basically, watch the class. It's good. And I'm bias!