“Does it help you to know that you’ve ruined my day?” “It does, yes.” - Larry Niven

Here is where the predictions failed: We didn't take Cargo Cult mentality into account: "if somebody has something I don't, he must have stolen it." We didn't understand how good we could get at communication — when you have something that someone else doesn't, the whole damn planet knows it.

Drugs: “There’s no way to keep them from getting in. Anyone who wants drugs can get them. We make arrests where we can, and so what? Me, I’m betting on Darwin.”
“How do you mean?”
“The next generation won’t use drugs because they’ll be descended from people who had better sense.”

"They used to teach us that evolution of intelligent beings wasn't possible," she said. "Societies protect their weaker members. Civilizations tend to make wheel chairs and spectacles and hearing aids as soon as they have the tools for them. When a society makes war, the men generally have to pass a fitness test before they're allowed, to risk their lives. I suppose it helps win the war." She smiled. "But it leaves precious little room for the survival of the fittest."