I'm exactly the opposite. Whenever I see a project consisting of 50,000 lines of code, I am amazed that somebody had the stamina to bite down and actually write

I'm exactly the opposite. Whenever I see a project consisting of 50,000 lines of code, I am amazed that somebody had the stamina to bite down and actually write all that code. I could never imagine myself writing 50,000 lines, I'm way too lazy for that. Fifty-thousand lines? You could write a universe in that, with a high-level language like Python (or in assembly, a smallish planet). Semi-kidding aside, it's part laziness and part DRY-principle. I hate writing code twice, even if it's two chunks with similar functionality. If they are so similar (in an abstract way), there's probably a reason for that, and I try to capture that reason into my code by unraveling the similar parts from the specific parts. That usually makes it smaller. Can you imagine what happens if those 50K lines (comments/white-space aside) all implement nearly unique functionality? Those 64k demos linked upthread are what happens. I'm going to guess those are 100K-250K lines C++ [1], maybe? But then, a prize-winning 64k probably does a little bit more than a basic partial Minecraft engine :-P Since you're asking "how do their minds work?", maybe I can get a little bit obsessive over this optimizing (wouldn't call it OCD--that would trivialize the disorder), but I do really get a slight "mind itch" if I notice code with duplicate functionality. [0] Sometimes it doesn't. But often there's other advantages, too. If that's not the case either (or I'm on a deadline), I grit my teeth and write the duplicate code, but I try to make it really obvious that it is duplicate. That way at least it'll compress well :P [1] Not even the 4K demos use pure assembly any more, compiler tricks and exe packers have become amazing in the past decade since I stopped making them. Not counting the external procedural/generative design tools/Werkzeuge, btw.