Coffee contains caffeine, which acts as a stimulant. For this reason, it is often consumed in the morning, and during working hours. Students preparing for examinations with late-night "cram sessions" use coffee to maintain their concentration. Office workers take a "coffee break" whenever their energy is diminished.
http://en.wikipedia.org/wiki/Coffee
What separates us from the animals?
yes
Addictive?
yes
Do you want coffee now, just by reading this?
yes
Backbone of modern civilization?
yes
