Writing is a better way of thinking

Reading maketh a full man, conference a ready man, and writing an exact man.
- Francis Bacon, 16th century English philosopher

Bacon's point here is to say that while reading prodigiously will "fill" you with ideas and information, it is only when you are called upon to discuss those ideas and facts that you really apply them. More than this even, writing forces you to master your thoughts, to organize them and refine them, so as to express them clearly and concisely. It is this process that makes writing enjoyable (at least for me), and gives me a sense of satisfaction, that I have managed to say at least one thing with precision. It is also that wrangling with words, that wrestling which culminates in a satisfying victory, that probably spurred one poet to say

I hate writing, but I love having written.
- Dorothy Parker