I told them I was leaving because I couldn't support my family on what they were paying me and what they were paying me was sooooo far below market level that it wasn't fair compensation (I got a 60% raise for a lateral move). I told them that if they didn't improve their pay soon, they were about to lose several other people in my area.

A few months later I met up with some of those guys and they said that their salaries had recently gotten a nice bump.