I recently had to do linear algebra for the first time ever irl. I’ve been out of school for ~15 years. I was trying to make a rotation matrix to transform some points in 2D space. It took me a very long time to remember how it’s performed yet alone “transformation matrix” which is something I’d never heard of before. I got my code all working and was so proud, then later found that one of the r packages I was using could have just solved it all automatically :/