Did you ever have a teacher who presented material in a way that led to you have an epiphany, where the concept just clicked?

- Like realizing that the derivative of a waveform at a point is simply the slope of the waveform at that point
- Or understanding that the integral of the waveform is simply the area under the curve
- Or how negative feedback makes an amplifier predictable
- Or how a dielectric affects capacitance

What concepts do we now take for granted that when you first came across them, they were magic?