In terms of number of times executed, the most impactful code I've written was a JavaScript GUID generator used on the Xbox One for launch and for a few years after. It was simple code that a colleague showed me, but had to be written in native code and then exposed over WinRT. Anyway, I built the DLL on my personal machine and forgot to set it up on a build machine. Microsoft doesn't like shipping private binaries for a number of reasons and, well, a nice build engineer found me about a month after launch and let me know. This DLL was used by just about every JavaScript app on Xbox One at launch.