Do you even cycle?

There are several reasons to do this:

• Most of the sensors that make the lights change will not sense bicycles, so the light will never change.
• In many places, getting a jump on the car traffic between the light and the next is much safer, because you are getting passed mid-block instead of at the intersection, where you are much more likely to be hit by a turning car.
• Jumping the light usually means being noticed by drivers while you are moving and they are not, which is great because drivers are notoriously bad at noticing at noticing anything smaller than a 7-11 when they are moving. I have been hit 4 times while stopped at stop signs and red lights, three of which while IN MY CAR, because drivers simply cannot be trusted to pay attention.
• Usually waiting at the light with the cars means the car in front of you is belching exhaust right into your face.

I now live in a city with very good cycling infrastructure, and a vast majority of people wait for the light, because when the infrastructure is designed well, it is safer to do so.