This is Solomon & Corbit's opponent-process model, shown in illustrative mood units — a way to see the mechanism the lesson describes, not a real substance, a dose in milligrams, or medical advice.
A drug creates a fast “push” you feel as the high. Your brain answers with a slow counterweight — fewer, less sensitive receptors — that grows with repeated use. What you actually feel is the difference: push minus counterweight.
So the same push does less as the counterweight climbs (that is tolerance); chasing the high with bigger doses drives the counterweight higher (escalation); and stopping leaves the counterweight in place after the drug clears — a baseline stuck underwater (withdrawal) that heals only slowly, over days.
Quit and wait, and the counterweight fades. Dose again after that and it can hit surprisingly hard — your tolerance reset while you were away. The numbers here are illustrative, tuned so the mechanism is visible in a minute of play.
Something in the simulation stopped unexpectedly — the lesson continues without it. Nothing you did was wrong; you can move on.