I was always one of those finicky game masters who always had to plan everything out in advance. In my youth, I felt that randomly generated results from a table didn't "produce good story" or some other ridiculous high minded bull honkey. But I'm also not someone who would completely rely on tables to stock a dungeon ("This room has... *clatter* 60 gibberlings and... *clatter* a pie crust filled with silver pieces.") or run social encounters. For me, random tables are imagination boosters. If I'm ever feeling lost or out of ideas when I'm constructing an adventure, I can always find someone's table full of dice-generated good ideas. For players, they can provide character hooks, equipment ideas or ideas
Probably my favorite random table out there comes from Ken Hite's phenomenal Savage Worlds campaign setting, The Day After Ragnarok, which details a pulpy post-apocalyptic world where Hitler's occult machinations actually summoned the monsters of Norse myth, forcing the Allies to slam a nuclear bomb into the Midgard Serpent. When the Serpent dies, it crushes Western Europe underneath its body and sends a venom-infected tidal wave towards the East Coast of North America. If you're a Savage Worlds fan, an alternate history weirdness fan or just a Ken Hite fan, you should really check it out.
Anyway, the back of the Day After Ragnarok book has a random Adventure Generator in it that really hits the right buttons for me. Each aspect of an adventure is detailed here, from the initial Hook that gets the PCs involved (anything from the Dying Message to an Innocent Beginning that belies something more sinister) to the antagonists involved or a potential Twist to add. But the best part of the Adventure generator is that it's fairly system-neutral: those they have references to setting items like Chimeras (monsters that were once human like ghouls and Stalinist man-ape hybrids) and the like, it's very easily adaptable to just about any setting. If I run out of ideas for Bullets and Tequila adventures, I'm gonna pull this thing out.