I irritated a walker once. Anyway cycling along and there was said lady walking along canal path. I slow down and wait for opportunity to pass. Old lady heard me and moved to the side so I said "cheers" as I passed. No sooner had I thanked her she started ranting about how I should have made alerted her somehow. (clearly I did?). I returned fire with obscenities matched only by Bismarck's main guns. Also gave the flying V over my shoulder as I could hear here continuing to mutter her pedantry as I cycled off.
Same procedure, similar circumstances as when passing everybody else, yet spectacularly different attitude with this particular individual. I felt she hated cyclists so I had to try my best to justify that hatred. I bet her whole day was ruined lol! Because I know how some people get so upset over daft crap.