…caffeine…reduces the lethargy and catalepsy that is normally induced by accumulated adenosine in your brain. Eventually you must pay the piper (the adenosine is still there, waiting on the sidelines, for the caffeine to be metabolized, then it resumes its duty), which is why you typically feel a spike in tiredness about 6 hours after drinking coffee.
A caffine:adenosine hack I learned a couple years ago is to slam a cup of coffee right before you take a 20 minute nap. The sleep cycle expunges the adenosine from your brain and by the time you wake up the caffeine is fully in your system doing its job of inhibiting (now at minimal levels) adenosine.
The thing with coffee is that it has chemical components which other substances of similar caffeine content (e.g. tea) don’t have; these are the chemicals which cause the ‘jacked up’ sensations. Even Buddhist monks who engage in lengthy meditations will drink tea to remain alert but not hyper-stimulated.