It's this fair thing. The people who pay us believe it's fair to pay us as little as possible. Walk in and say I'm not being paid a fair wage, and they's look at you sideways and say, Yes you are. Point out those who are paid more, they'll point out those who are paid less. If they are vaguely competent you'll walk out agreeing with them. If they are good you could end up with a pay cut!
Go in and say I want to be paid more, how do we make this happen, negotiate from strength. Asking for fairness is negotiating from a position of weakness. Don't do it.