Happened to me twice in London too!
It’s because everyones staring at their stems trying to smash out a Strava segment.
First was at a pedestrian crossing. The guy just said “i thought you were going to go through the light!” as if it was my fault.
The second time was on Embankment in London and a car was turning left up ahead, so i slowed down really gradually, put my hand out to warn people, but someone about 3 cyclists back was too busy racing, fell into the main carriageway and a bus swerved to avoid him. He got up laughing.
I now tell people not to draft me too. Some people get in a right huff, and respond with a “it’s called drafting mate” or something then cycle off really fast. WTF