Stopped on Lea Bridge Road to help some guy who'd set out without a spare tube or pump and had punctured. Found a chunk of glass in the tyre, got the tyre back on, pumped to ~6 bar with my minipump, said goodbye and rode on in a smug haze thinking "my good deed for the day"
Five minutes later, cycling through the park, taking evasive action to avoid an erratic minihuman on a miniscooter, had the bike slide out sideways underneath me on some wet leaves and went straight down on thigh and elbow. Conclusion: "karma" is not actually a thing
(Slightly sore, no lasting damage, bike unharmed. Could have been worse)