My story:
I worked for a company that paid a bit below market salaries, for the SF Bay Area. I was on a team with two more junior engineers. At one point one disclosed to me that they felt underpaid. That led to a salary discussion where I explained that the company habitually underpaid people, and I was happy to share my salary with them so they would know they're not the only ones underpaid (and also, implicitly, so they'd know if they were getting taken advantage of, since I'm all about employees looking out for each other).
As it turned out, however, I was making around 40% more than both of them. Some of that was due to more experience, but it was more a matter of me being underpaid versus them being outright screwed. Naturally they went and asked for a well-deserved raise, and the company, of course, said no.
This changed the team dynamics in a fundamental, toxic way. It engendered bitterness from them not only toward the company but to me as well, which ultimately led to all of us leaving the company for greener pastures but with lots of bad feelings all around.
You could say the takeaway is don't work for companies out to screw their workers, but that's most of them.