Cache consistency and memory consistency are two areas that are maximally annoying to deal with and, other than perf, are the most pissing match-centric areas of computing you can encounter
@ljs cache coherency issues are one of my favorite security bug types, it's like memory time travel, you can see past states of memory or make memory contents change out of nowhere
@ljs very annoying that some CPUs have magic hardware fairies that just make it all coherent
@jann x86 must piss you off haha