It was too large and too complex for the kinds of things I needed to do. I over focused on getting better with my tools rather than working on domain problems.
Since it has affordances for speed, it encourages one to make fast code, but this is rarely needed. Making fast code is a trap.
Trying to become good or very good at something also puts you in direct competition with others doing the same thing. I did not have time to compete, so it wasn't a big differentiator for me.
C++ helped me learn when do give up, and when to refocus my attention in areas where I can have greater impact. I wish I was a little more technically and philosophically mature before I undertook C++. Having concrete goals is a huge clarifier and allows one to judge something with a much better light.