Caffeine is an interesting topic.It seems to me caffeine works by making more dopamine available to reward goal-completion. That explains why caffeine makes a person more productive.However, it seems to me as if dopamine encourages top-down goal oriented thoughts, which takes attention away from things like awareness of physical sensations, sensory input, other people’s states of mind, and davening, which all involve a bottom-up inking of something that isn’t particularly stimulating or pleasurable, and so is pushed out by anything more engaging.So, caffeine might have a side effect of reducing a person’s ability to engage in these activities.