I'd love to know opium's secret relative to morphine/codeine, in the really extended half life, that isn't matched by concurrent usage of CYP-P450-3A4 and CYP-P450-2D6 inhibitors, pod tea lasts ages, much longer than oral morphine in a similar dose.
I don't know about fun, doing the a/b, it gets kinda tedious, workups, when you've done so fucking many of them that its just another headache necessary in getting from A to D via B, C etc. Especially for things more complex than plant extractions, such as multi-step syntheses (say, benzaldehyde, nitroethane+amine base-knoevanagel condensation run under microwave irradiation, followed by vacuum-distillation off of surplus nitro, washing out the base with ice-cold glacial acetic acid, then multiple aliquots of ice-cold water, recrystallization from isopropanol and iPA/H2O dual-solvent recrystallization, then heating to 80 'C for 2.5 hours once the melting point test is up to scratch and ideally TLC, in a thick slurry of iron dust in glacial acetic acid, with a catalytic quantity of ferric chloride hydrate, to give phenylacetone [P2P, 1-phenyl-propan-2-one, starting from 1-phenyl-2-beta-nitropropene], first forming the water insoluble bisulfite adduct, after washing with concentrated NaCl brine, solvents etc, liberating the adduct with a weak base like carbonate, extraction of the P2P into DCM, washing and drying of the DCM before distilling it off and recycling the DCM, vacuum distillation of the ketone, followed by forming the ketoxime with hydroxylamine salts and a base to deprotonate the hydroxylamine, then tedious crystallization [oximes really can be tough cookies to crystallize some times], isolation and careful, thorough dessication of the ketoxime, dissolution in rigorously dried, absolutely anhydrous ethanol and, keeping it cold, slowly adding, over the course of hours, the correct quantity of sodium metal, divided up into lots of little tiny chips a few mm in diameter, working under dried inert atmosphere to reduce it to amphetamine.
When you've seen that much workup for a single synthesis, it can get old, believe you me. And thats not counting vacuum distillation of the amphetamine base, formation of a salt, and multiple recrystallizations to give racemic amphetamine sulfate or phosphate. Even then, there is still the option of going further, although never have, in order to crystallize with enantiopure tartaric acid and resolve the racemic amphetamine chirally to afford dexamphetamine.
And that isn't a particularly long or arduous synthesis even. Just a bog standard amphetamine synthesis, although not the only way of doing it. Workups get old, fast