Imagine having complete mastery of your feelings. How liberating and empowering would that be? You would possess the ability to abruptly terminate troublesome feelings and self-trigger euphoria, or at least achieve cessation of negative thoughts and emotions.
Can you imagine having switches at your fingertips to precisely control how you feel? You could shuffle off into a corner and literally burn out your brain’s pleasure centres. But let's assume that the device also replenished your dopamine stocks - you wouldn’t experience the crash that accompanies crude narcotics, and you could circumvent the depressive after-effects of natural methods. Normally, the come-down deters or at least moderates repeat indulgences. In the case of the machine however, dopamine bursts could be triggered continuously - until you just died, probably a few days or weeks later.
If you consider that for most of us life is a quest for pleasurable sensations, would a machine that could produce those sensations on demand render life - at least life lived the customary way - pointless? Might such a pleasure machine eliminate our species more efficiently than any war or virus? After all, we would want the pleasure. And, feeling constantly ecstatic because of it, we would probably be very resistant to cautionary advice.
I imagine society would disintegrate within a few years if such a device were ever made available to just a portion of any population. But such a device would certainly sell well!