A major problem in many global trouble spots is large numbers of refugees (both official, or legal, and unofficial, or illegal). Some areas are worse than others. The Middle East and Africa are very unpleasant places to live, just ask the millions of people who have tried to flee those regions for a better life, or to escape certain death. The nations in the region are not only worth fleeing, but they are not very receptive to refugees. Thus most refugees are seeking new homes in the West, including Israel. But many of these refugees run out of money, or ideas, before they reach the West, and end up in some other (but marginally better) Middle Eastern or African country.
Egypt, for example, has 39,000 official (being cared for largely by international agencies) refugees (mainly from Sudan, Iraq and Somalia). But there are believed to be over 400,000 illegal refugees, many just waiting for an opportunity to flee to a wealthier, and more accommodating country.
Some countries are major exporters of refugees. Iraq, for example, has produced over 1.5 million refugees since 2003. Most of these are Sunni Arabs, often supporters of Saddam Hussein. The majority Shia Arabs sought revenge on the Sunni Arabs, especially after the Sunni Arabs began a terror campaign in 2004, in a failed effort to regain power. The other major source of Iraqis are several hundred thousand Christian refugees. These people were chased out by Islamic radicals, who hated all non-Moslems, and Shia Arabs are angry at the support Iraqi Christians gave to Saddam Hussein. There were also 30,000 Palestinians chased out of Iraq, again because of their support for Saddam Hussein.
Then there are the seven million Palestinian refugees. These are largely the descendants of the 600,000 Palestinians who fled the newly formed Israel in the late 1940s. At the time, an equal number of Jews were expelled from Arab countries. All these Jewish refugees found new homes, most of them in Israel. But Arab countries would not accept the Palestinians as migrants and insisted they remain refugees. Many still live in segregated towns ("refugee camps") and are still considered foreigners in countries where they have lived all their lives. The Arab nations of North Africa don't discriminate. Any refugees trying to enter are either forced back, or treated as refugees and foreigners forever. The Arab tradition of hospitality only applies to brief visits.
The North African nations, and Yemen, mostly have to deal with African refugees from the south. Yemen gets lots of people from Somalia and Ethiopia. The North African nations have millions of Africans trying to get to Europe. The North African Arabs will not try to integrate the African migrants, and either try and catch them and send them back south, or let them pass on their way to Europe.
All these refugees stuck in Arab countries are, and long have been, a source of unrest and, at times, outright rebellion. Local security forces, as a result, tend to treat these refugees quite harshly, which is another reason most refugees, especially from sub-Saharan Africa, just want to pass through. The Palestinians would like to go back to Palestine (as they call the Palestinian territories and Israel). But the Israelis won't cooperate, and its difficult getting legal entry into Western nations. The Palestinian tendency to support terrorist groups makes it difficult for them to get asylum in the West.