Why is chemical dependence bad? Countless people are highly dependent on caffeine for example. I can see perhaps if it isn't managed and doses escalate out of

Why is chemical dependence bad? Countless people are highly dependent on caffeine for example. I can see perhaps if it isn't managed and doses escalate out of control, that's when off target effects really take over. How about running out of the substance and needing to go through withdrawal (readaptation)? Perhaps tolerance escalates too quickly and you lose the beneficial effects? All of these things can be managed by coming up with a dosing plan to maintain concentrations in the therapeutic window, using easily obtainable substances, and cycling on and off of the compound to maintain the beneficial behavioral and psychological benefits.