Almost invariably, when very bright people have not studied philosophy and seen multiple ways of building a framework to understand something, they form some amateur understanding of their own on the topic and consider it to be so commonsense that it seems like idiocy to them to significantly deviate from it. While the recent conversation in which I was reminded of this was about mathematical "knowledge", where I argued against what might've been a naïve form of logical positivism and for a particular form of empiricism. It's difficult to successfully discuss these things though with people who haven't encountered other whole ways of looking at things, and I don't think I did a good enough job in giving enough food for thought to most of the listeners to inspire them to look into all the ways of thinking about things. A lot of the time when I'm talking with philosophy, I'm looking more for consideration of the ideas I present than agreement, at least partly because I find it disappointing when people argue passionately for their weltanschauung when they've never take the time to really understand/consider other ways of seeing the same thing. There are certain things they would probably not say and certain types of groupthought they would not engage in, I think, if they saw the viability of competing frameworks. This is part of why I think "teaching" philosophy is so important in High School and University.
It's important to note that this learning isn't something that people get all at once - exposure to radically different ways of seeing fields usually has to happen once per field to be effective. Before I took the Philosophy of Science class here at CMU, well after I finished my undergrad, I was exposed to ideas that inspired me to reshape my notions of truth, learning, science, etc. Before that, I may have had some small ideas on possible variances in perspective, but I was relatively ignorant. I'm sure there are other areas of philosophy where I'm similarly ignorant - hopefully at some point I'll spot such areas and take classes or read books to remedy that.
Of course, what does it get me? I get to be the party pooper who tells people to hold their horses when they have passionate attachment to a certain way of looking at things, and I toss at them lone arguments they will laugh at until and unless they ever take to study the topic. It's probably a bit of walking into a church and arguing for atheism, or being the lone liberal in a room full of conservatives (or vice versa). Awesome... well, no, not really. I suppose it wouldn't go down well though to punt on discussion beyond a certain point and suggest books or classes in cases like this.