Just took the bike down the street less than a mile to grab lunch, and had to yell at 2 cars on the way back. One of them in the Kroger parking lot, not watching what he was doing. I yelled "HEY!" several times loudly and that got him to stop.
Then just down the street, which is a VERY narrow residential street, I'm talking barely 20 feet wide pavement, I see this d-bag trying to pass me right as we're approaching a stop sign. I hold my left hand out, palm backwards, but he still doesn't pull back. As he's right next to me (his windows are down) I yell out "Stay back!!" which got him to back off. There were a couple more stop signs before I got back to my office, and right before I got there I see the same guy coming from a side cross street. I passed him first, so despite him trying to take a detour he still ended up behind me.
He was going straight across so wasn't actually behind me as I pulled back into the office parking lot.