This one is obvious, but still my favorite, Mr. Mackey's lesson on drugs where the bag of herb goes missing, Mackey is fired, ends up homeless, hits up a joint, tries lsd and actually starts to live a good life. Principle Victoria, et. all, try to rescue him from a honeymoon in India to a granola lady and send him to rehab where they recondition him to believe that drugs are bad, mmmkay.