Caffeine is often referred to as the number one used drug in the world. One of the main reasons people consume coffee is for the caffeine present in the drink. We as a society crave that alertness and boost that comes from the caffeine found in coffee.
The reasons caffeine makes us feel so alert is because it is a stimulant. It raises the level of nerve activity in your body and this is why we often times feel the need to consume this drink in the mornings.