For example:
- Positive: The substitute teacher can choose what days they would like to work.
 - Fact: Substitute teachers only get paid for days they do work, and work is not available every day.
 - Potential Negative: If the substitute teacher chooses not to work on a particular day, who is to say that a job will be available when the sub chooses to work.
 
Another example:
- Positive: The substitute teacher goes to work in the morning, and goes home at night, and does not have the office politics to worry about.
 - Fact: The substitute teacher is only with students and fellow teachers a day at a time.
 - Potential Negative: The substitute teacher has to work especially hard to develop relationships with the students, teachers and faculty.
 
Now for the personal side...
I love substitute teaching.  I learn so much.  The flexibility is a benefit, and my personality jives with the occupation.  I have never been happier in a paying job than I am right now..  as a a substitute teacher.
Please join me on my travels, learning as I teach, and teaching as I learn!