@PyrolyticCarbon
I've had scared jumps or anger with many combination of "excuse me", the bell, loud misadjusted brakes, shifter clicking.
I think those reactions happen when people feel threatened. When I sneak up and then say "excuse me", that leads to jumping and makes me feel bad. I can see how someone might respond with "fight", rather than "flight".
When I warn ten seconds in advance (like tapping my super loud brakes while still far away), the reactions are always orderly.