How can I pose this question so that you hear it in the way it is intended? It is indeed an essential question to be asked at first by a person raised in a different tradition who is first taught the first thing about Islam: that Islam includes already the religions of Christianity and Judaism and supersedes them, in essence. Please correct me if I have overstated this.
Out of this, perhaps overstated, premise I ask honestly: has it not occurred to Muslims that by telling Christians and Jews their religions have been superseded by the newer set of beliefs that is Islam, these Jews and Christians might be rather offended and unwilling to learn and listen or even smile?