NOTE When you assign post to a subcategory, make sure you pick the subcategory only, not the parent
category. That means that if you want to add a post about green tea, you should turn on the checkbox next to
the Green Tea box, but not the Tea box. Because Tea is the parent category, people who browse the Tea category
will automatically see your Green Tea posts.
NOTE Yes, you can create subcategories inside of subcategories. But doing so can complicate life and make
it more difficult to fit a proper category tree in your sidebar. If possible, stick with one level of subcategories