I believe that the most common reason for terrorism in any of its forms is terrorism caused by religious extremisms. Those who follow a belief so obsessively do not see anything beyond that, and everything outside of that belief is wrong and heresy. This affects the relationship that these supporters may have with the rest of the world and with people from their own community as well, which often concludes in violent terrorist acts since they believe that this is the way to put a limit on sinners. This type of terrorism is widely seen in the Middle East.
