By playing the lights, I don't mean that I get through without getting reds. The lights in my area are not timed or synchronized, they each have their own controller.
What I mean is that when I see a light ahead turn red, I start coasting down. Sure, this drops me below the speed limit. But the limit is not meant to have you approach a red light at the limit and lock the brakes to be able to stop without sliding through or hitting the cars already stopped there.
By playing I mean coasting to a light which is already red in front of me. By coasting I do NOT lower the average speed way down below the average of roaring up to the light and coming to a dead stop. If I get through the light at 20mph because it turns green just as I get there, I generally pull ahead of the guy next to me who rushes up and stops and waits at a dead stop.