Before going to bells, I used to shout "on your left." Many people would jump out of their skins even when I shouted from a considerable distance. With a bell, most people do not appear to jump but silently move to the right. Many wave as I pass and some actually say thanks. I usually wave and say thanks as well. When I am walking and a cyclist passes, I much prefer to hear a bell. There is something about a shout that is surprising and alarming.