Selective hearing works wonders in those situations.
JAM: "Hey biker!"
Me: *Turns around*
JAM: "Can you move over so I can get by?"
Me: "Huh?"
JAM: "I SAID, MOVE OVER SO I CAN GET BY!"
Me: "Sorry, WHAT???"
JAM: "It's a shared lane. Read the signs".
Me: "Pardon?"
And so on, until the light turns green.