I miss the days when JavaScript frameworks could be built with a simple npm install and executing a Grunt/Gulp file. Now to build Angular I need Yarn, Java, Bazel, and hundreds of megabytes of additional tooling downloaded by the build script. On a slow connection it takes ages to download everything, and even then the build often fails (on Windows I have yet to get it working successfully).

Edit: I'm referring to building the framework itself (e.g. to contribute a fix). Building an Angular project with the CLI works quite well.