>Something we missed until now in this thread is the experiments of Volta etc.. But I don't know how you could "distill" that into one thing. Maybe it would be frog legs. But that still begs the question of how to not fail at seeing the electric phenomena.
Electricity itself isn't much use without a lot of prior groundwork behind it. Ancient Greeks knew about static electricity. But to make electricity do useful work, you still need machines that are actually doing the work, which requires industrialization, plus you need materials like copper wires, iron, lead, nickel, zinc, etc. And you need to have enough math to describe the laws of electricity to do any kind of serious engineering.
The development of electricity was ASTOUNDINGLY fast in Europe. In the span of about 25 years Europe went from not knowing much more than the Greeks about the phenomenon to figuring out electrical induction, electrolysis of water, batteries, and then the formal mathematical law to express the forces between moving currents was worked out by Ampere. Then waves were theorized (by Maxwell and others), discovered shortly after, and wireless technology was born.
In the span of about 100 years from 1800 to 1900 Western civilization went from knowing virtually nothing about electricity to understanding it essentially the same way we do today.