Many years ago my wife, who had just gone into the Army Reserve, was on a training mission in the South, and this other woman who saw her noticed her Bible. The other woman, unfamiliar with Judaism, asked whether that was a Jewish Bible, and when she was told yes, asked if she could look at it. After a while, she exclaimed, "Why, that's just the Old Testament!" She really didn't know! People's ignorance of Judaism amazes me. I recently had an experience that reminded me of this story.
Yesterday I made a trip to the Library of Congress to get information for a Website I manage. On my way back home, I was waiting for a bus together with a woman when one of those Mormon missionaries approached us. (For some reason, most of these Mormons have the title "Elder" on their badge, though an "elder" would seem to be something you'd become after attaining a significant age, and these people are rarely more than about 20!) At first, he was talking about mainly the weather, not religion at all, but then he asked us if we were Christians. The woman answered yes, but I said that I was Jewish, and that changed the flow of conversation from what, I'm sure, the Mormon missionary had been prepared for. He remarked that he was not very familiar with what Jews believed, so I went into some explanation, and it was really my direction for the rest of the conversation. Now when I talk to ignorant Christians and Mormons, I generally go to the negative differences because they are easier to explain: we don't accept the New Testament (and in this case I added "and certainly not the Book of Mormon," which elicited a surprised response, because the missionary probably expected that I'd never heard of the Book of Mormon; he asked me if I'd ever read it, and I told him, "some parts," which is true), and Jesus was to us just a man who started off as a Jew like us, who started a new religion that we don't accept (a lot like the mainstream Christians' attitude to Joseph Smith, though I did not bring that point up).
About that time, the bus arrived, and it seems the missionary was not getting on, but the woman and I did, and afterward she told me that she was not aware of what I'd said, that Jesus was a breakaway Jew! We talked for some more, and I told her that I don't believe in trying to convince others to chainge their religion; I think everyone else has to believe what they think is right. But I'm happy, when asked, to tell people what I believe, so I had no problems with this discussion. (Since neither the Mormon missionary nor the woman was particularly hostile, just ignorant, this was the case.)
I think that one foundation of my religious beliefs is a passage in the 95th Psalm, which is part of the Jewish Sabbath Eve liturgy: Verse 7 says that when God speaks to us we should listen, and I think this means that God still does try to speak to us. And this is the foundation of my belief that "what seems right to you is what you should believe," because it is God speaking to you that tells you this.
But the main point of this story is that it's amazing that people in this country are so ignorant of the relationship between Judaism and Christianity. That someone who considers herself a Christian can be so totally unaware of the fact that Christianity is, historically, a branch off the tree of Judaism simply amazes me.