Hmm,
The first one was eons ago. I was coding in Pascal and discovered System interruptions. The “Ahaha” was when I realized it’s easy to store CPU state and invoke whatever the fuck I want on any memory pointer. I loved my 2 silly animations running side by side on 80286.
Most recent : Finally understanding how “Expression” works in C# and how it can be combined into a Lambda and compiler does the whole heavy lifting on types compatibility and more.