One thing I think I missed, was how pleasant it it is to program in modern C++. There are no pointers, for the most part completely automatic memory management (with the RAAI) idiom. Build systems are still a pain. I recently built a physics simulator for an n-body type interaction problem in C++. Not a a large program (about 40K lines of code) but the experience was extremely pleasant. For build I used a combination of make for Linux and macOS and nmake and VisualStudio projects. Debuggers on Linux are still a bit bad. GDB with Emacs is fine but, is somewhat primitive compared to VisualStudio and even Xcode. Other than that it was a joy to actually write in C++.

The primary reason, I think was because there was no legacy code I had to deal with.