General reasoning - general reasoning, but coffee contains not only (and sometimes not so much) caffeine, but also other active substances. Not all of them are stimulating. Depending on individual sensitivity, type and method of preparation of coffee, the ratio of effects may be different.
In addition, even pure caffeine has a far from unambiguous effect. For example, it acts on the great vessels in one way, on the peripheral ones in a different way. In general, such a difference is not so rare.
Quote from the pharmacological reference:
In the neurochemical mechanism of the stimulating effect of caffeine, it plays an important role the ability to bind to specific ("purine" or adenosine) receptors in the brain, the endogenous ligand for which is the purine nucleoside - adenosine. The structural similarity between the caffeine and adenosine molecules contributes to this. Since adenosine is considered to be a factor that reduces arousal in the brain, replacing it with caffeine leads to a stimulating effect. With prolonged use of caffeine, the formation of new adenosine receptors in the brain cells is possible, and the effect of caffeine gradually decreases.
Coffee is an easy drug, and the drug has both a coming (raising the mood, relieving fatigue) and a withdrawal. But the breakdown is mainly increased drowsiness, irritability and lethargy. When I didn't drink coffee systematically, from 1 cup I could crawl out onto the ceiling and stay awake for a day, but now I drink 2-3 cups and go to bed calmly. Does not produce the expected tonic effect and is consumed only out of habit