I can relate to these not so nice feelings. I worked for the state government, and our salary information is published online free for everyone to view. I would search for my co-workers and be pissed by the fact that they made more money than I did since I felt I worked harder than them and smarter too.
It provided me with incentive to move forward and find work that paid me more, or an organization that would value my services more.
Looking back though, I think that my feelings were perhaps not wholly warranted. It was clear that people were earning more mostly because they had been at the office much longer than me, and because they were older and much more experienced. I did notice, though, that there was a bit of a gap based on race and gender.
Salary transparency can be a double-edged sword that provides you incentive to ask for more, but can poke your ego and make you think you deserve more than perhaps you actually deserve for the value you are providing.