Once upon a time in a land not too far from here people were worked twelve hours a day and they had one day a week off. They got no holidays with pay. If they got injured on the job, they lost the job. In many cases if a person died on the job their family lost their housing because the local houses were often owned by the largest employer.
It was not uncommon for women to get a knock on the door and her husband's body would be brought in. Then they would tell her she had three days to have the funeral and get out of the house. (This is all well documented.)
Slowly people, miners at first, started trying to organize to get better treatment. Many were shot. The government sent out troops on more than one occasion to prevent the workers from unionizing. One time in the mountains of West Virginia workers were actually bombed!
Very, very slowly they succeeded in organizing. Eventually, they won rights like an 8 hour work day and overtime pay. Worker's compensation and death benefits. Following WWII most businesses had a very paternal (socialistic almost

) attitude toward their employees and the need for unions sort of waned. For the most part any way. But, unions really kept the businesses from regressing when they really tried to. This really depended on the industry.
By the 70s things had gotten pretty bad with the unions. Some had gotten very corrupt and the leaders were making huge amounts of money. During the 70s it did get pretty bad and unions caused some real problems. But, they continued to do some good with issues of employee exposures to toxic things and injuries. Then came the Reagan years.
Many corporations hired advertising firms to discredit the unions. There was ample fodder. They did such a good job that unions who really had a legit beef lost public support. Then Reagan broke the air traffic controllers union. This was a real shame, the controllers had serious concerns that got ignored for another ten years.
Then corporations were allowed to buy businesses and "utilize" the pension funds. Supposedly they were going to honor the obligations at some later point with the vast amounts of money they would make if they had complete control over that money. 90% of the businesses lost it all.
The beat goes on though. There are huge contracts held by advertising companies to bad mouth unions. There are lobbyist firms that have massive budgets solely to defeat anything union in congress.
This will start a huge fight, but the in GM union issue most people ignore the fact that a.) the huge chunk that people get mad about that is pension debt wouldn't be an issue if the firm had not been allowed to raid the existing pension funds in the 80s their fund had been completely self funding! b.) GMs money troubles are because they formed GMAC and bought DITECH at the height of the bad mortgage market.
Their bankruptcy doesn't have squat to do with cars! Or unions. Now, more than in the last 30 years we need unions. Look at how well the CEOS did with no one protecting the employees. We should trust them ?
Sorry this is so long. I did a thesis on this topic ten years ago, and routinely deliver three hour lectures! Consider yourself lucky to have gotten off easy!!

But, you asked.