Arab nationalism means that the people and countries of the Arab World, from the Atlantic Ocean to the Arabian Sea, constitute one nation and are bound together by their common linguistic, cultural, religious, and historical heritage. Their use for Modern Standard Arabic as the main written language and the Islamic faith predominance consequently meant for the ideology that they have a common culture. One of the primary goals of Arab nationalism is the end, or at least the minimization, of direct Western influence in the, so called, Arab World, and the removal of those Arab governments considered to be dependent upon acquiescence to Western interests to the detriment of their people. Unfortunately, this nationalism is just a banner or a logo that has never been applied in practical light. The Arab attitude and the Arab Israel conflict is the best example of how well this nationalism works.

What happened between Iraq and Kuwait is a part of the unwanted Arab nationalism. Kuwait and Iraq had a serious territorial dispute that led to armed warfare in 1973 and again in 1976. Iraq wanted Kuwait's oil and ports, and argued that Kuwait was rightfully theirs due to pre-British imperial boundaries. In 1990 Iraq occupied Kuwait, but was expelled in 1991.

Another example of our claimed nationalism is The Iran–Iraq War. In this war Syria entered on the side of Iran, against Iraq, with aid and supplies. All other Arab countries except for Libya, the United States and Western World, as well as the USSR and Warsaw pact supported Iraq, imposing embargoes on Iran. The war ended after 8 years, when after Iraq, Iran accepted a resolution of the UN asking for the halt of military activities. The frontiers were re-established to those before the war.

What is happening in Lebanon and Iraq nowadays is a proof of the absence of the Arab nationalism. Because of religious and ethnic tensions, Lebanon became socially unstable. Interference from the outside, mainly Western, exacerbated the situation and caused a civil war. The civil war spanned over two decades and grabbed the attention of the world through abductions of Westerners. Ultimately the United Nations decided to intervene. By trial and error the situation ultimately got under control, but tensions still rest in the Lebanese society, and although the war ended, the risk of civil war is still present. In 2003, the United States, the United Kingdom, Australia and Poland invaded and occupied Iraq after a dispute over the status of the Iraqi Nuclear, Biological, and Chemical weapons programs. This war is sometimes known as the Second Gulf War.

The Arab–Israeli conflict explains further the Arab nationalism. It spans roughly one century of political tensions and open hostilities, though Israel itself only was established as a sovereign state in 1948. The conflict involves the establishment of the Zionist movement and the subsequent creation of the modern State of Israel in territory regarded by the Jewish people as their historical homeland, and by the Pan-Arab movement as belonging to the Palestinians, be they Muslim, Christian, Druze or other (and in the Pan-Islamic context, in territory regarded as Muslim lands).
The conflict, which started as a political and nationalist conflict over competing territorial ambitions following the collapse of the Ottoman Empire, has shifted over the years from the large scale regional Arab–Israeli conflict to a more local Israeli-Palestinian conflict, though the Arab World and Israel generally remain at odds with each other over specific territory.
Until now, Israel has raided and destroyed facilities, houses and cities in major urban centers in the Palestine. This including taking many parts of land. In July 2006, Hezbollah fighters crossed the border from Lebanon into Israel, attacked and killed eight Israeli soldiers, and abducted two others as hostages, setting off the 2006 Lebanon War which caused much destruction in Lebanon. A UN-sponsored ceasefire went into effect on August 14, 2006, officially ending the conflict.[53] The conflict killed over a thousand people, mostly Lebanese civilians, severely damaged Lebanese civil infrastructure, and displaced approximately one million Lebanese and 300,000–500,000 Israelis, although most were able to return to their homes. After the ceasefire, some parts of Southern Lebanon remained uninhabitable due to Israeli unexploded cluster bomb lets. On September 6, 2007, in Operation Orchard, Israel bombed an eastern Syrian complex which was allegedly a nuclear reactor being built with assistance from North Korea.[64] Israel had also bombed Syria in 2003.
This is just a picture of the existing Arab nationalism where Arab countries and leaders fall apart, looking merely for individual interest and sharing a feeling of hatred and hostility forgetting their absolute enemy, Israel.How could we be silent watching those Palestinian victims being mercilessly killed in massacre by Israel. We must take a serious steb regarding our Arab nationalism and work honestly for the sake of our beloved nation.

Sources
1-wikipedia
2-Answers.com, Arab Nationalism