According a study to the University of British Columbia's Department of Psychology, the effects of a morning coffee or espresso as a stimulant to sharpen a worker's concentration and work product won't necessarily work on every worker. The study found that caffeine and other similar stimulants (like amphetamines) don't actually raise motivational levels in the workplace. For employees who are naturally motivated toward their jobs, a morning dose of caffeine might actually have the reverse effect and turn them into slackers. So, if you're normally a productive person, think twice about having a doppio-dose of espresso.
Sometimes, the best rewards come from loving your job...