Health
Ergonomics
As someone doing repetitive motions, such as sitting at a computer and typing, or sitting at a desk and writing, it will do you good to learn about the health problems these activities can cause. Here are a very few links to relevant web pages (to be considered as a starting point). This is serious stuff. Learn, or suffer.
A good starting point might be to find out about
Repetetive Strain Injury at Wikipedia.