I don't know, I'm finding Calculus ties a lot of earlier math together. The quadratic equations that I thought were a weirdly specific thing to spend so long drilling (ok so parabolas can describe kinematic arcs, what's the big deal?) come up again and again in differential equations.

The relationships between area and volume of various objects I spent geometry trying to understand make much sense as integrals.

Trig, logarithms, exponentials, infinite series, they all come into themselves when you start applying them to analysis. It just all sorta clicks once you start to thread them together.