In high school, I read a book called The Thousand Year War in the Mideast by Richard Mayberry. The author explains that the mindset of the people in the Arab world is different from that of those in the West–they have a much greater focus on and remembrance for the past. Something like the Crusades, which to us is past history, is a current event to them. I think understanding this is crucial in our engagement of the Muslim world.
Also, Westerners often see historical events, particularly negative ones, as something they are not responsible for. In some ways they are right; no one alive today took part in the Crusades. But it was Westerners (and so-called Christians) who committed all the heinous atrocities that Muslims still remember today. It is not until we as a collective group acknowledge what our civilization and religion did in the past that we will be able to have meaningful engagement with the Muslim world.