Why: Because you're not a car.
Look...just because you wear a yellow spandex shirt does not make you Lance Armstrong and does not make Hillcrest one of the stages of the Tour De France. And your arm thing as some sort of turn signal? Really? Who came up with that? Yes, I know you're turning left. You know how I know? Because you're in front of me in the left turn only lane! Seriously...why did we build you the Katy and White Rock Trials? Oh, I'm sorry, do the runners slow you down?!