This research has resulted in the faddish use of caffeine among some and a generally positive impression of caffeine that is not completely warranted. While caffeine may still be a fad among runners it has a long history of use among cyclists. Although touted as an almost miracle performance enhancer make no mistake about it, caffeine is not for everybody. To avoid this habituation drink caffeine only during or before races and training. Most road cyclists limit their caffeine consumption to a bottle of coke diluted with water during training rides and the last half of longer races or a cup of drip coffee a half an hour before shorter races.
Caffeine affects different people differently.
For some it only causes uncomfortable 'nervousness', high blood pressure and stomach acid. A strong cup of coffee, to someone who does not drink caffeine regularly, can last all day and well into the night, leaving a groggy feeling the next day which can be remedied only with another cup. If you do drink more than a cup of coffee every day some cutting back would probably go far towards improving your riding quality. When a cup of coffee is no longer an option but a prerequisite for alertness and energy it is probably doing more harm than good. This is the negative side of drinking the stuff, moderation can be difficult.