>>418785220
>You did understand it at some point in time, but generally that'll be hard 10 years later, unless you are meticulous with your documentation.
>I imagine reading complex old code is almost like reading someone else's code. Because the you of the past is basically that.
Programming is all about processing data. If you just explain the main insight briefly, you can reverse engineer your own code. 
And if you don't use the code for 10 years, is it really useful?

>>418785186
Code is just a tool to access the processing power of your computer. 
Everything built upon it is a tradeoff between performance and ease of use. 
I'm not a fetishist, I don't jerk-off to C++ or asm, I just used to them after using them extensively. 
>more than you can explain why creating your own rendering is absolutely essential.
But I can. The gist is "if you don't understand how things work, you are going to get bad performance, bugs and an unexceptional result overall". 

>>418786202
What is your expertise then? You don't even know that your CPU is doing 80% of the time. Are you not embarrassed of yourself?
Windows kernel is not that complicated, and actually a well written part of windows btw. Just so you know.