I only read a few responses, but here's mine anyway.
I was riding in a clearly painted bike lane next to a sidewalk. A pedestrian who I was approaching stepped in front of me without first looking left at the road. I suppose she thought she had a few feet of margin before any (motorized) vehicles were a danger. I had about a half second to react and plowed straight into her, going down hard in the process, and came up swearing. She was ambulatory so she got up and got the hell out of there immediately so as not to hear a lecture/rant. Did not give a fig whether I was injured or not.