Glorious caffeine, the world's most widely used psychoactive substance, enjoyed by humans since as early as the Stone Age. It's a fun and practical pick-me-up that keeps drowsiness at bay and restores alertness. For us, anyway. For the poor little insects who encounter caffeine in the plants they feed on, it paralyzes and kills. Next time you're enjoying a coffee and pastry, toast the less fortunate. Cheers!