Pedestrians who can't hear me politely call out "On your left" on the MUP's because they are wearing head phones. This is super irritating, especially since many of them are also not maintaining a straight line. Sometimes i've had to make a last minute decision to whip around to the right or lock up my brakes because the people are oblivious. I mean I try to be courteous and pass at reasonable speed's but the walkers/joggers and other cyclists need to do their part as well, at least turn the music down so you still have some audible connection to the world around you.