Worst: BB was clicking, so I decided to go to this shop which is out of the way, but run by an ex-keirin racer, so worth it. Anyway, as I said its pretty far, and on my way I reach an area where I have to go against traffic, so I get on the sidewalk. I reach a section where there is a tree on one side and a guardrail on the other, here (in Japan) lots of business use these really tall flags to advertise their businesses, they are about 5ft tall by 1.5 wide, these are attached to the guardrail about every 10 feet. As I'm riding through this narrow spot the wind suddenly shifts and the flag flies directly toward me. I have bullhorns, and they get wrapped up and my wheel is suddenly perpendicular to the top tube. I fly over the handle bars, sprain my wrist and break my arm.
I ride back the way I came with one hand, and stop at a different bike shop to sit down for a while and have the BB replaced. They use the wrong BB and I struggle home with one hand.

Best: group ride through Tokyo while the cherry blossoms were blooming.