Caffeine is a stimulant. It increases overall neurological activity. And as such it generally tends to amplify the effects of any other mind altering substances you might be on.
I know that my vibe is a lot faster paced, and a little less focused, when I've had an energy drink before I smoke a joint. And I feel it stronger for the same amount of smoking.
How do you feel about amazing weed, amazing coffee/tea/morning beverage of choice, and an amazing sunrise/quiet morning/personal time/get high and drive?