I had reserved the book "Why We Love Dogs, Eat Pigs and Wear Cows" at my local library. When I stopped in at the desk to pick it up, the librarian chuckled when she read the title, and said "that's true." Rather than just get my book and continue on, I seized the opportunity.
I smiled and said that I have been a vegetarian for 15 years and that was just the latest book in the field that I was going to read. She was surprised and asked "Do you feel better being a vegetarian?" I replied that I do, but not because of health, but because I'm against cruelty to animals (which raised her eyebrows). Then I followed it up by saying that you can't possibly eat an animal without being cruel to it.
At that moment she was a little shocked at my reply and it seemed like an "ah-ha" moment. I left hoping that the seed that was planted would be allowed to grow.
Just saying things like that can have a profound impact on someone. Perhaps they have never had someone speak so candidly about food to them. Maybe they have never thought of their food choices being associated with cruelty toward animals (and let's face it, the vast majority of people would probably say they are against animal cruelty, but they haven't yet made the connection).
So go forward and plant seeds! You never know who they will touch and what impact and ripple effect it can have. They can certainly be a great way to further the cause of animal rights.