Where I live there are a lot of narrow lanes, no paths and not much traffic, when I approach a walker I usually say/shout "Hi, I'm cycling on your left/right" they will invariably jump to the same side! I've only had a few mutterings about a bell, to which I normally reply that I think a bell is less polite.
On my ride a couple of days ago I came across a lady leading her horse to a field with a second, unharnessed horse following in its' own good time. She was quite flustered when she saw me approach and very grateful when I stopped and said I would wait for her to sort the horses out, it took all of 2 minutes and I went on my way, all of us happy.
On the other hand, using a shared use path (something I rarely do, but for some reason the new bridge over the Taw at Barnstaple has incredibly narrow lanes and very impatient drivers) and a male pedestrian deliberately stepped in to my path, still haven't worked out why, I just moved across to the pedestrian side, gave him a "cheers mate" and a smile (I thought that would annoy him more than anything else - I could see he was itching for me to get aggressive) and carried on.