I think my problem is that I'm way too diplomatic, way too accommodating in dealing with these people. George L.'s advice to "start acting better than the other guy" is something I've always done -- especially with obnoxious higher-ranked aikidoka -- but doing so, it seems, often only encourages their obnoxiousness. I'm thinking now that, with certain individuals, giving as good as I'm getting is more appropriate than turning the other cheek.
I've often been described as "too diplomatic," the implication (as I take it) is that folks like that are too docile...the proverbial last-place finishers in life. I disagree with that assumption, though I do understand there's a grain of truth to it. In my opinion, it seems that if you're starting to be affected by things like this more than in the past, yeah a new approach is probably needed. Personally, I'm a big fan of transcending the "problem", but that doesn't mean ignoring it, like so many people seem to think...in fact my "understanding" of Aikido is essentially that we transcend a given problem by connecting with it directly. We institute change upon a situation when it's unhealthy or otherwise incorrect...again, per my "understanding." Of course, I'm sure the other fellow felt he was doing just that.
All that said, in my opinion, the way to best handle situations like that is transient. In the education field we often talk about the concept of "teachable moments." Usually it's meant to describe a diversion from the issue at hand to teach something tangential, but important in and of itself. However, I think it includes the implication that there are times which are not good to teach, even if it directly relates to the topic at hand, and that we must strive to understand these situational relationships if we desire to actually teach something meaningful.
I'm reminded of a story a sempai told me where he was training with a karateka who had come to a seminar. They were doing munetsuki sumiotoshi but the karateka kept pulling his punches so the technique wouldn't work properly. Sempai told the karateka to punch with more sincerity and he did...apparently with the intent of teaching sempai a lesson, but sempai "corner dropped" him and, while the karateka was shaken up by the experience, i'm sure he learned something useful; which was to his benefit as much as to my sempai's, if not more so. Now, I've experienced a couple situations where I've been taught in a less than pleasurable manner, and I gotta say, for a person like me who is quick to let go of most things, it took me a while to enjoy training with those personalities again, even if they were making a valid point. It's all in how you handle it I guess.