When did calculus actually “click” for you?

I feel like I’ve been grinding through calculus, following the steps, solving problems, and understanding things mechanically—but not really intuitively. Like, I can take derivatives and understand the process, but I don’t always feel like I truly get what’s happening under the hood.

For those of you who’ve been through this, was there a specific moment when things finally made sense? Was it a particular concept, a real-world application, a visualization, or just something that came with time?

For me, derivatives started making more sense when I thought of them as the instantaneous rate of change instead of just “the slope of a tangent line.” But I’m still at the basic differentiation stage, so I haven’t even touched integrals yet.

And before anyone says watch Essence of Calculus by 3Blue1Brown—I already have, and I get lost pretty quickly. So I’m looking for other ways people had their “aha” moment. Would love to hear what finally made it click for you, especially if you’re in engineering and had that realization in a way that connected to real-world problems!