1. When I finally understood how event loop in Javascript works for the very first time, I had an Aha moment on the language design. 2. When I read about how g

1. When I finally understood how event loop in Javascript works for the very first time, I had an Aha moment on the language design. 2. When I read about how garbage collection works in V8 Javascript engine, I had an aha moment about how hard things are just one layer below my working area. 3. When I started learning Rust, had another aha about how the language is designed without GC. I never thought that was possible in a language. These maybe simple things for many, but I have no educational background in any of these, so I'm amazed by things that people actually got used to.