Things you wish you could unlearn from c++ after learning rust.

I am learning c++ and want to learn rust. c++ has a lot of tech debt and overily complicated features. What are some c++ things you learned that looking back, feel like you learned tech debt? What are some c++ concepts you learned that should not be learned but are required to write modern c++? Rust highlights alot of the issues with c++ and i know there are alot of c++ devs on this subreddit, so I would love to hear your guys' thoughts.