Unions. Those oh-so controversial groupings that some folks just love to hate, others hate to love, and the news just loves to broadcast.

Why the controversy?

These are the folks who brought you the five-day work week and the 40-hour full-time job (according to the bumper stickers). They also get blamed from time to time for holding up progress in other ways. Beyond that, some people just don't like the idea of unions, and some states don't have them at all (we're looking at you, Virginia).

According to Diane Ravitch, teachers' unions came about because of low pay, poor work conditions, and exploitation of female teachers simply because they were female and often when they were having a baby. Which means that unions, in their original permutation, had a lot to do with protecting teachers from exploitive practices.

Regardless of how folks feel about unions, their purpose is to protect teachers and teachers' rights. Many unions work to help increase teacher pay, shore up benefits, advocate for teacher rights, provide members with legal services, and keep work environments positive. And they also work to help improve education and rigor in the classroom, as well as to keep class sizes low and promote scientifically sound pedagogy.

But it wouldn't be worth an article if there weren't some complaints. Many folks cringe when they see the big bucks union leaders make. Others complain about how unions advocate against merit pay. And there are times when the actions of teacher unions create havoc in a community. Remember when Chicago teachers went on strike? Yeah, that was a havoc situation if we've ever seen one. Finally, lots of people say that unions make teachers lazy—they don't go above and beyond because they don't have to.

Whatever your position, unions have been around for long enough that they're probably not about to disappear anytime soon.

#sorrynotsorry, depending on how you feel about it.