I find myself in those same situations! But because I am a psychologist, I'm used to say that I have some kind of tag on my forehead saying "Feel free to share! It's my job to listen!" :D Most of times, I get late to wherever I'm going because I don't want to be rude also and stop whatever the person is saying... But on the other hand, as I live in a small village, it's good to hear what people have to say, you get to know a lot about the community and the village :) So I usually listen for a while and then say "Sorry I'm running late now!" :D