I hated precalc, but I loved proof-based linear algebra, my first university math course (linalg + multivariate calc). The simplicity(/beauty) of matrix multip

I hated precalc, but I loved proof-based linear algebra, my first university math course (linalg + multivariate calc). The simplicity(/beauty) of matrix multiplication still irks me though, in the sense of "wow, seriously? when you work it out, it really looks that simple?"