Hmm ..I would say let's try and look at this in a positive light. Take it as a training opportunity. Though other riders can sometimes be frustrating, the reality is we need to be able to control our horse in stressful or anxious situations because we can't always control the environment. And this trail ride gave you the opportunity to improve your skills and build confidence in both you and your horse. I would agree that maybe it was a little 'rude', I always let others know if I'm coming up on them, or if plan to trot or lope, but some people really just do not know any better and do not realize the importance of it. Although these types of rides may not seem ideal, they will probably teach you more and improve your horsemanship a lot more than a simple walk down the trail, not to say there's anything wrong with an easy relaxing ride, those are always nice. :) But challenges are what really make you grow and get better. As we all know, there's always room for improvement when it comes to our horsemanship skills.