It depends on the situation. For instance, some T intersections in my area have pointless lights. There usually isn't anyone on the road with green and hardly any traffic. And, the light sensors aren't all bike friendly, so they don't change. In cases like that, I do a slow roll.

I see people blow through lights all the time without any regards to other cars or bikes on the road. It's only a matter of time until they become a statistic and I become a witness on the police report. Then we all get read another "I got hit by car today!" thread.