I've felt similarly when reading Strang's book. It takes a lot of effort on my part to understand what he is trying to say but once I get it - it feels obvious.

I've felt similarly when reading Strang's book. It takes a lot of effort on my part to understand what he is trying to say but once I get it - it feels obvious. And I think a lot of linear algebra is like this since there are many different ways to say the same thing and it can get confusing if someone is not holding your hand. I wish I had a recommendation for you.