Pros
Lack of certainty for future employment makes for a fun-filled day/week/month. Lack of pay increases encourage thrifty spending and creative ways to make dinner from a 4kg bag of potatoes. Lack of training makes you seek out ways to learn on the job; like Wikipedia and YouTube. Lack of career progression and threats of redundancies make you appreciate your job. Enforced leave over the Christmas period means more time with family.
Cons
Lack of certainty for future employment discourages workers from taking well need vacation time. Lack of pay increases encourage poor productivity and belligerence Lack of training ensures you do a half arsed job. Lack of career progression and threats of redundancies make help you toward an early grave. Enforced leave over the Christmas period means more time with family.