Something for my next job

Seems kind of obvious now, but I liked this suggestion from Monster.com:

Keep a journal of your daily reactions to your job situation, and look for recurring themes. Which aspects of your current job do you like? Dislike? Are these related to the work, your company culture or the people with whom you work?

I'm basically trying to do the same thing now, but being so far removed from the past situations I wonder how accurate I'm being in my assessments.