No two conflicts are the same and to say that they have common causes or common history belittles the interests of each group and the better (in their view) world that they strive to create. However, there are general patterns that conflicts tend to have, even though not every conflict has every one of these components and most do not have all of them. This list is not exhaustive:
1) Imperialism: This is the idea that a given country or nation has as its destiny to grow and to mature both physically and spiritually. That expansion naturally brings new regions under the authority of this state and causes conflict with those who refuse to submit to the new power.
2) Revanchism: This is the reverse of imperialism. An empire in its last days begins to see parts of its territory splinter off as supposed independent regions. Those who support the maintaining the virtue of a great composite empire strive to protect what was and create a future that continues that legacy.
3) Independence: When one group of people have been under the yoke of another and suffered too many grievances, the people realize that what they need is the ability to determine their own destiny on their own land to rectify the situation.
4) Revolution: This is the same as independence, except the oppressed group sees themselves as the natural leadership of the nation in question instead of needing to break away. All citizens should be able to gain the benefits they seek.
5) Ethnic Hegemony: One ethnic/religious/national group are the true patriots and representatives of the country. Other groups should have fewer rights or a country less-geared to their interests. The reverse of this is citizenship and equality, but that usually falls under "Revolution". Also, this ethnic/religious/national group may be repressed in neighboring countries and it is incumbent on this nation to protect and defend them.
6) Sacred Values or Territory: A country represents a religious virtue or contains religiously sacred territory. There is something that is naturally hallowed about a certain stretch of land or a certain faith and understanding of the Divine and thus it is worth defending for those who revere its sanctity.
7) Idealism and Pragmatism: Many people believe in higher ideals and aspirations as to what a government can achieve or do. Others believe they have the most pragmatic solution to any given crisis. However, not everyone believes that this solution is desirable, especially interests vested in the Ancient Régime that have benefits from the less-effective system.
8) Strategic Positioning: The particular geography of a country is not conducive to defense of that country, therefore modifications must be made to ensure the long-term stability and security of the country. It could also be that resources exist in a foreign country that could stabilize a given country or defend against a third country and the given country must take advantage to secure their survival.
9) Power: Some people are just intoxicated by the idea of increasing power and will oppose those who threaten their natural ascent to this ideal.