A missing element to the conversation is another interpretation of DOD, that is, domain-oriented design. My favorite writing on the matter is "Programming as if

A missing element to the conversation is another interpretation of DOD, that is, domain-oriented design. My favorite writing on the matter is "Programming as if the Domain (and Performance) Mattered" (https://drive.google.com/file/d/0B59Tysg-nEQZSXRqVjJmQjZyVXc/view?resourcekey=0-TUcDaYWBXZ4WO4RtjTByBg https://drive.google.com/file/d/0B59Tysg-nEQZSXRqVjJmQjZyVXc...) When OOP has bad performance, or is otherwise another instance of ball of mud architecture, it often stems from not modeling the domain correctly. Only using or being forced to use an inferior conception of OOP (i.e. OOP as merely fancy structs + function pointers) doesn't help either, and ends up encouraging the sorts of patterns found in GOF even preemptively before they can maybe earn their keep. And what's especially insidious about Kingdom of Nouns style OOP is that just because you have named something, or created a type hierarchy, does not actually make it a particularly good model of anything. If you interview enough people, you'll find some thinking it's entirely reasonable to do the equivalent of making a Car a subclass of a Garage just because garages contain cars. When bad modeling infects production code, it's difficult to remove, especially when it's so overgrown that a bunch of other code is created not to fix the modeling but to try and wrangle a bit of sanity into localized corners (often at the further expense of performance -- frequently from a lot of data copying and revalidating). On the other hand, modeling things too close to the hardware, or (as the linked paper goes through) too close to one ideal of functional programming purity (where you want to just express everything with map and reduce on sequences of numbers if you can, in theory giving high performance too), can severely get in the way of changing things later, because again you're not actually modeling the domain very correctly, just implementing one clever and specific mapping to raw numbers. When the domain changes, if your mapping was too coupled to the hardware, or too coupled to a nice map/reduce scheme, the change throws a big wrench in things. Sometimes, of course, such direct hardware and code exploitation is necessary, but we live in a fat world of excess and most business software isn't so constrained. An interesting example from the past could be Wolfenstein 3D, where its doors and especially its secret push walls are handled as special cases by the raycaster. Carmack initially refused to add push wall functionality to his engine, it seemed like it would be too big of a hack and possibly hinder performance too much. Big special cases as ifs down in the fors usually suck. After much needling and thinking though, and realizing the game really did need such a feature, he eventually got it done, surprising everyone when at a final attempt at convincing him to add them, he revealed he already did it.