Love of coffee could also get you hooked on drugs - so beware, warn scientists.
Those who respond well to caffeine, found in energy drinks too, often enjoyed the effects of amphetamines and cocaine, especially in high doses, says a new study.
Not everyone who enjoys caffeine will abuse cocaine, they added, but the stimulating effects of these drugs make them particularly vulnerable, the journal Drug and Alcohol Dependence reports.
The study is based on a group which was asked if it preferred caffeine to a placebo tablet. It was then given a type of amphetamine and asked to rate it. Most who liked the caffeine liked the drugs.
Stacey Sigmon, professor at Vermont University, US, said: "People differ dramatically in how they respond to drugs... a single dose of a drug can produce completely opposite effects in two people with one absolutely loving and the other hating the drug's effects.