> I got a B in Linear Algebra, and I still can't describe why you'd need that in the real world, [...]

Here is a short list of applications of linear algebra:

   - Balancing chemical equations
   - Input–output models in economics
   - Electric circuits
   - Graphs
   - Least squares approximate solutions
   - Computer graphics
   - Cryptography
   - Error-correcting codes
   - Fourier analysis

You can read about these in Chapter 7 of my book in LA. Here is an extended preview of it here: https://minireference.com/static/excerpts/noBSLA_v2_preview....