Anesthesiology resident here. When I was in medical school we had a professor of psychiatry who specialized in addiction. At one point in one of his lectures he put up a pictoral representation of dopamine (and other neurotransmitter) release by normal pleasurable stuff (sex, food, etc.). Then he compared that to methamphetamines which produced a spike that was a clean order of magnitude higher than anything else. Than he turned our addiction lecture on his head and said something to the affect "imagine feeling a pleasure beyond your wildest pleasure, a comfort beyond comfort, and sensation of good will beyond even intimacy....that is kind of what doing meth gets you. We've developed a reward system that was designed to reward activities important for our survival but these drugs mimick and exceed the signal caused by a good thing. Thus, our brain associates survival with the drug. So you can't blame addicts. They've been to Everest. Normal things in life...the simple pleasures, they're mole hills in your back yard. They are mundane. How can you logically convince someone who has been there that his life is better without going to Everest again, without that feeling of pure ecstasy. Forget about the horrendous withdrawal that will make you feel like shit. 10 years out, an addicts brain remembers, these drugs affect your primitive brain because they literally associated drugs with life."