Why were nations imperalistic?

I don't think there can be any logical reasoning for why a nation would be imperialistic, however many nations adopted this philosophy because their homelands could not support the needs for natural and limited resources. Such a nation is England, which could not produce many resources it needed, and so it began to colonize much of the world in order to take those places' resources. This is one main reason for Imperialism in many nations from the beginning of the Age of Exploration up until the end of World War II and the fall of many remaining empires.