There are these two young fish swimming along and they happen to meet an older fish swimming the other way, who nods at them and says “Morning, boys. How’s the water?” And the two young fish swim on for a bit, and then eventually one of them looks over at the other and goes “What the hell is water?”
David Foster Wallace, from This is Water
A fish is swimming along, having some breakfast, when suddenly he’s snatched out of his world by his food, into a bright world where it’s hard to breathe, landing on the bottom of a boat, where strange alien creatures make odd sounds. Overhead, he sees an airplane flying at 500 mph (without knowing what “airplane”, “flying” or “500 mph” means). Suddenly, one of the creatures picks him up, removes the pain, and, just as suddenly, he’s back home. Yet, when he regales his friends with this tale, no one can believe such a strange world could exist.
This talk describes the water you swim in but cannot see anymore, like relational databases and application servers. Additionally, it jerks you out of safe, warm water (briefly) to describe a strange, fantastical world with things like immutable database server, phoenix machines, and lambdas.
You may have trouble getting your friends who didn’t attend to understand.