Unions are only effective if the members are miserable. Don't believe me? Try to get support for a strike from people that are perfectly happy with their job.
Keep that in mind when you are making a decision about a job. In order for union leaders to get your support, they have to convince you that you are miserable enough to quit your job (temporarily) or life won't get any better.
I know that is a bitter view of unions, but if you think long enough you'll see a lot of truth to it.