Everyone gets discouraged. Everyone has off days. Frankly, writers work in a vacuum a large part of the time, so it's easy to lose our perspective in a lot of ways.
That's why I love getting slapped in the face with reminders that anything really is possible. Recently, news has come from the medical community about a new way of approaching cancer treatments where doctors reprogram our bodies fight cancer on its own, much like we're able to fight back against colds. Results have been incredibly positive so far. Cancer is insidious, and while it's hardly the only dangerous set of diseases humans can get, any progress that keeps people from dying is for the good.
These scientists never gave up. They took what seemed like an insurmountable problem and kept attacking it until they finally got results they wanted.
It's this kind of dedication and hard work that I fight to remember on bad days. It's something we should all remember.